模块整理笔记

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1、模块定义

用来从逻辑上组织python代码(变量,函数,类,逻辑:实现一个功能),本质上就是.py结尾python文件

分类:内置模块、开源模块、自定义模块

 

2、导入模块

本质:导入模块的本质就是把python文件解释一遍;导入包的本质就是把包文件下面的init.py文件运行一遍

① 同目录下模块的导入

#同级目录间import

import module_name              #直接导入模块
import module_name,module2_name     #导入多个模块     使用:模块名.加函数名
from module_name import *           #导入模块中所有函数和变量等。。不建议使用
from module_name import m1,m2,m3        #只导入模块中函数m1,m2,m3  使用:直接使用m1,m2,m3即可
from module_name import m1 as m   #导入module_name模块中m1函数并且重新赋值给m  使用:直接输入m即可

不同目录下模块的导入

#不同目录之间import  当前文件main.py

#目录结构
# ├── Credit_card
# │
# ├── core  #
# │   ├── __init__.py
# │   └── main.py  # 当前文件
# ├── conf  #
# │   ├── __init__.py
# │   └── setting.py
# │   └── lzl.py

import sys,os

creditcard_path=os.path.dirname(os.path.dirname(os.path.abspath(__file__))) #当前目录的上上级目录绝对路径,即Creditcard目录
sys.path.insert(0,creditcard_path)    #把Creditcard目录加入到系统路径

print(sys.path)                      #打印系统环境路径
#[‘C:\\\\Users\\\\L\\\\PycharmProjects\\\\s14\\\\Day5\\\\Creditcard,.......]

#import settings.py                   #无法直接import
#ImportError: No module named ‘settings‘

from conf import settings           #from目录import模块

settings.set()                        #执行settings下的函数
#in the settings

不同目录下模块连环导入 

不同目录多个模块之间相互导入,为什么要引入这个概念,虽然老师没讲,但这个很重要,当时做atm程序时一个很大的坑........

目录结构:

技术分享
目录结构
├── Credit_card
│
├── core  #
│   ├── __init__.py
│   └── main.py  # 当前文件
├── conf  #
│   ├── __init__.py
│   └── setting.py
│   └── lzl.py
目录结构

conf目录下的文件:

技术分享
#!/usr/bin/env python
# -*- coding:utf-8 -*-
#-Author-Lian

#当前文件lzl.py
def name():
    print("name is lzl")
lzl.py
技术分享
#当前文件settings,调用lzl.py模块
import lzl              #导入模块lzl

def set():
    print("in the settings")
    lzl.name()              #运行lzl模块下的函数

set()                       #执行函数set
#in the settings
#name is lzl
setttings.py

此时执行settings.py文件没有任何问题,就是同一目录下的模块之间的导入,关键来了,此刻croe目录下的main.py导入模块settings会出现什么状况呢??!

core目录下的文件:

#不同目录之间连环import 当前文件main.py
import sys,os

creditcard_path=os.path.dirname(os.path.dirname(os.path.abspath(__file__))) #当前目录的上上级目录绝对路径,即Creditcard目录
sys.path.insert(0,creditcard_path)    #把Creditcard目录加入到系统路径

from conf import settings

settings.set()                        #执行settings下的函数
#    import lzl              #导入模块lzl
#ImportError: No module named ‘lzl‘

可以看到直接报错:ImportError: No module named ‘lzl‘,想想什么会报错类?!刚才已经说到了,导入模块的本质就是把模块里的内容执行一遍,当main.py导入settings模块时,也会把settings里的内容执行一遍,即执行import lzl;但是对于main.py来说,不能直接import lzl,所有就出现了刚才的报错,那有什么办法可以解决?!

对conf目录下settings.py文件进行修改

技术分享
#当前文件settings,调用lzl.py模块
from . import lzl              #通过相对路径导入模块lzl

def set():
    print("in the settings")
    lzl.name()              #运行lzl模块下的函数

set()                       #执行函数set
#in the settings
#name is lzl
settings.py

此时执行main.py文件

#不同目录之间连环import 当前文件main.py
import sys,os

creditcard_path=os.path.dirname(os.path.dirname(os.path.abspath(__file__))) #当前目录的上上级目录绝对路径,即Creditcard目录
sys.path.insert(0,creditcard_path)    #把Creditcard目录加入到系统路径

from conf import settings

settings.set()                        #执行settings下的函数
# in the settings
# name is lzl
# in the settings
# name is lzl

没有任何报错,我们只对settings修改了lzl模块的调用方式,结果就完全不同,此时的from . import lzl 用到的是相对路径,这就是相对路径的优点所在

不同目录多个模块相互导入,用相对路径

 目录结构:

技术分享
Day5
    ├── Credit_card
            ├── README.md
            ├── core 
            │   ├── __init__.py
            │   └── main.py 
            ├── conf 
            │   ├── __init__.py
            │   └── setting.py
            │   └── lzl.py        
目录结构

conf目录下的文件:

技术分享
#!/usr/bin/env python
# -*- coding:utf-8 -*-
#-Author-Lian

#当前文件lzl.py  相对路径
def name():
    print("name is lzl")
lzl.py
技术分享
#!/usr/bin/env python
# -*- coding:utf-8 -*-
#-Author-Lian

#当前文件settings,调用lzl.py模块  相对路径
from . import lzl              #通过相对路径导入模块lzl

def set():
    print("in the settings")
    lzl.name()              #运行lzl模块下的函数

set()                       #执行函数set
#in the settings
#name is lzl
settings

core目录下的文件:

#不同目录之间连环import 当前文件main.py  相对路径

from Day5.Credit_card.conf import settings


settings.set()                        #执行settings下的函数
# in the settings
# name is lzl
# in the settings
# name is lzl

lzl.py以及settings.py文件未变,main.py文件去掉了繁杂的sys.path添加的过程,直接执行from Day5.Credit_card.conf import settings,使用相对路径,更加简洁方便!

 

 

二、内置模块

1time和datatime模块

时间相关的操作,时间有三种表示方式:

  • 时间戳               1970年1月1日之后的秒,即:time.time()
  • 格式化的字符串    2014-11-11 11:11,    即:time.strftime(‘%Y-%m-%d‘)
  • 结构化时间          元组包含了:年、日、星期等... time.struct_time    即:time.localtime()

time模块:

#time模块
import time

print(time.time())              #时间戳
#1472037866.0750718

print(time.localtime())        #结构化时间
#time.struct_time(tm_year=2016, tm_mon=8, tm_mday=25, tm_hour=8, tm_min=44, tm_sec=46, tm_wday=3, tm_yday=238, tm_isdst=0)

print(time.strftime(‘%Y-%m-%d‘))    #格式化的字符串
#2016-08-25
print(time.strftime(‘%Y-%m-%d‘,time.localtime()))
#2016-08-25

print(time.gmtime())            #结构化时间
#time.struct_time(tm_year=2016, tm_mon=8, tm_mday=25, tm_hour=3, tm_min=8, tm_sec=48, tm_wday=3, tm_yday=238, tm_isdst=0)

print(time.strptime(‘2014-11-11‘, ‘%Y-%m-%d‘))  #结构化时间
#time.struct_time(tm_year=2014, tm_mon=11, tm_mday=11, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=1, tm_yday=315, tm_isdst=-1)

print(time.asctime())
#Thu Aug 25 11:15:10 2016
print(time.asctime(time.localtime()))
#Thu Aug 25 11:15:10 2016
print(time.ctime(time.time()))
#Thu Aug 25 11:15:10 2016

结构化时间:

技术分享  

时间戳、格式化字符串、机构化时间相互转换:

 技术分享

datetime:

import datetime

print(datetime.date)    #表示日期的类。常用的属性有year, month, day
#<class ‘datetime.date‘>
print(datetime.time)    #表示时间的类。常用的属性有hour, minute, second, microsecond
#<class ‘datetime.time‘>
print(datetime.datetime)        #表示日期时间
#<class ‘datetime.datetime‘>
print(datetime.timedelta)       #表示时间间隔,即两个时间点之间的长度
#<class ‘datetime.timedelta‘>

print(datetime.datetime.now())
#2016-08-25 14:21:07.722285
print(datetime.datetime.now() - datetime.timedelta(days=5))
#2016-08-20 14:21:28.275460

更多-》》https://zhuanlan.zhihu.com/p/23679915?utm_source=itdadao&utm_medium=referral

 

2、random模块

生成随机数:

#random随机数模块
import random

print(random.random())      #生成0到1的随机数
#0.7308387398872364

print(random.randint(1,3))  #生成1-3随机数
#3

print(random.randrange(1,3)) #生成1-2随机数,不包含3
#2

print(random.choice("hello"))  #随机选取字符串
#e

print(random.sample("hello",2))     #随机选取特定的字符
#[‘l‘, ‘h‘]

items = [1,2,3,4,5,6,7]
random.shuffle(items)
print(items)
#[2, 3, 1, 6, 4, 7, 5]

验证码:

import random
checkcode = ‘‘
for i in range(4):
    current = random.randrange(0,4)
    if current != i:
        temp = chr(random.randint(65,90))
    else:
        temp = random.randint(0,9)
    checkcode += str(temp)
    
print(checkcode)
#51T6

 

3、os模块

用于提供系统级别的操作

#os模块
import os

os.getcwd() #获取当前工作目录,即当前python脚本工作的目录路径
os.chdir("dirname")  #改变当前脚本工作目录;相当于shell下cd
os.curdir  #返回当前目录: (‘.‘)
os.pardir  #获取当前目录的父目录字符串名:(‘..‘)
os.makedirs(‘dirname1/dirname2‘)    #可生成多层递归目录
os.removedirs(‘dirname1‘)   # 若目录为空,则删除,并递归到上一级目录,如若也为空,则删除,依此类推
os.mkdir(‘dirname‘)   # 生成单级目录;相当于shell中mkdir dirname
os.rmdir(‘dirname‘)    #删除单级空目录,若目录不为空则无法删除,报错;相当于shell中rmdir dirname
os.listdir(‘dirname‘)    #列出指定目录下的所有文件和子目录,包括隐藏文件,并以列表方式打印
os.remove() # 删除一个文件
os.rename("oldname","newname") # 重命名文件/目录
os.stat(‘path/filename‘) # 获取文件/目录信息
os.sep    #输出操作系统特定的路径分隔符,win下为"\\\\",Linux下为"/"
os.linesep    #输出当前平台使用的行终止符,win下为"\\t\\n",Linux下为"\\n"
os.pathsep    #输出用于分割文件路径的字符串
os.name    #输出字符串指示当前使用平台。win->‘nt‘; Linux->‘posix‘
os.system("bash command")  #运行shell命令,直接显示
os.environ  #获取系统环境变量
os.path.abspath(path)  #返回path规范化的绝对路径
os.path.split(path)  #将path分割成目录和文件名二元组返回
os.path.dirname(path) # 返回path的目录。其实就是os.path.split(path)的第一个元素
os.path.basename(path) # 返回path最后的文件名。如何path以/或\\结尾,那么就会返回空值。即os.path.split(path)的第二个元素
os.path.exists(path)  #如果path存在,返回True;如果path不存在,返回False
os.path.isabs(path)  #如果path是绝对路径,返回True
os.path.isfile(path)  #如果path是一个存在的文件,返回True。否则返回False
os.path.isdir(path)  #如果path是一个存在的目录,则返回True。否则返回False
os.path.join(path1[, path2[, ...]]) # 将多个路径组合后返回,第一个绝对路径之前的参数将被忽略
os.path.getatime(path)  #返回path所指向的文件或者目录的最后存取时间
os.path.getmtime(path)  #返回path所指向的文件或者目录的最后修改时间

 

4、sys模块

用于提供对解释器相关的操作

#sys模块
import sys

sys.argv           #命令行参数List,第一个元素是程序本身路径
sys.exit(n)        #退出程序,正常退出时exit(0)
sys.version       # 获取Python解释程序的版本信息
sys.maxint         #最大的Int值
sys.path           #返回模块的搜索路径,初始化时使用PYTHONPATH环境变量的值
sys.platform      #返回操作系统平台名称
sys.stdout.write(‘please:‘)
val = sys.stdin.readline()[:-1]

详情:->>http://www.cnblogs.com/lianzhilei/p/5724847.html 

 

5、shutil模块

高级的 文件、文件夹、压缩包 处理模块

① shutil.copyfileobj 将文件内容拷贝到另一个文件中,可以部分内容

技术分享
def copyfileobj(fsrc, fdst, length=16*1024):
    """copy data from file-like object fsrc to file-like object fdst"""
    while 1:
        buf = fsrc.read(length)
        if not buf:
            break
        fdst.write(buf)
shutil.copyfileobj
#shutil 文件拷贝
import shutil

f1 = open("fsrc",encoding="utf-8")

f2 = open("fdst",encoding="utf-8")

shutil.copyfile(f1,f2)

#把文件f1里的内容拷贝到f2当中

 shutil.copyfile 文件拷贝

技术分享
def copyfile(src, dst):
    """Copy data from src to dst"""
    if _samefile(src, dst):
        raise Error("`%s` and `%s` are the same file" % (src, dst))

    for fn in [src, dst]:
        try:
            st = os.stat(fn)
        except OSError:
            # File most likely does not exist
            pass
        else:
            # XXX What about other special files? (sockets, devices...)
            if stat.S_ISFIFO(st.st_mode):
                raise SpecialFileError("`%s` is a named pipe" % fn)

    with open(src, rb) as fsrc:
        with open(dst, wb) as fdst:
            copyfileobj(fsrc, fdst)
shutil.copyfile
#shutil.copyfile 文件拷贝
import shutil

shutil.copyfile("f1","f2")
#把文件f1里的内容拷贝到f2当中

 shutil.copymode(src, dst) 仅拷贝权限。内容、组、用户均不变

技术分享
def copymode(src, dst):
    """Copy mode bits from src to dst"""
    if hasattr(os, chmod):
        st = os.stat(src)
        mode = stat.S_IMODE(st.st_mode)
        os.chmod(dst, mode)
shutil.copymode

④ shutil.copystat(src, dst) 拷贝状态的信息,包括:mode bits, atime, mtime, flags

技术分享
def copystat(src, dst):
    """Copy all stat info (mode bits, atime, mtime, flags) from src to dst"""
    st = os.stat(src)
    mode = stat.S_IMODE(st.st_mode)
    if hasattr(os, utime):
        os.utime(dst, (st.st_atime, st.st_mtime))
    if hasattr(os, chmod):
        os.chmod(dst, mode)
    if hasattr(os, chflags) and hasattr(st, st_flags):
        try:
            os.chflags(dst, st.st_flags)
        except OSError, why:
            for err in EOPNOTSUPP, ENOTSUP:
                if hasattr(errno, err) and why.errno == getattr(errno, err):
                    break
            else:
                raise
shutil.copystat

 shutil.copy(src, dst) 拷贝文件和权限

技术分享
def copy(src, dst):
    """Copy data and mode bits ("cp src dst").

    The destination may be a directory.

    """
    if os.path.isdir(dst):
        dst = os.path.join(dst, os.path.basename(src))
    copyfile(src, dst)
    copymode(src, dst)
shutil.copy

⑥ shutil.copy2(src, dst) 拷贝文件和状态信息

技术分享
def copy2(src, dst):
    """Copy data and all stat info ("cp -p src dst").

    The destination may be a directory.

    """
    if os.path.isdir(dst):
        dst = os.path.join(dst, os.path.basename(src))
    copyfile(src, dst)
    copystat(src, dst)
shutil.copy2

⑦ shutil.copytree(src, dst, symlinks=False, ignore=None) 递归的去拷贝文件 拷贝多层目录

技术分享
def ignore_patterns(*patterns):
    """Function that can be used as copytree() ignore parameter.

    Patterns is a sequence of glob-style patterns
    that are used to exclude files"""
    def _ignore_patterns(path, names):
        ignored_names = []
        for pattern in patterns:
            ignored_names.extend(fnmatch.filter(names, pattern))
        return set(ignored_names)
    return _ignore_patterns

def copytree(src, dst, symlinks=False, ignore=None):
    """Recursively copy a directory tree using copy2().

    The destination directory must not already exist.
    If exception(s) occur, an Error is raised with a list of reasons.

    If the optional symlinks flag is true, symbolic links in the
    source tree result in symbolic links in the destination tree; if
    it is false, the contents of the files pointed to by symbolic
    links are copied.

    The optional ignore argument is a callable. If given, it
    is called with the `src` parameter, which is the directory
    being visited by copytree(), and `names` which is the list of
    `src` contents, as returned by os.listdir():

        callable(src, names) -> ignored_names

    Since copytree() is called recursively, the callable will be
    called once for each directory that is copied. It returns a
    list of names relative to the `src` directory that should
    not be copied.

    XXX Consider this example code rather than the ultimate tool.

    """
    names = os.listdir(src)
    if ignore is not None:
        ignored_names = ignore(src, names)
    else:
        ignored_names = set()

    os.makedirs(dst)
    errors = []
    for name in names:
        if name in ignored_names:
            continue
        srcname = os.path.join(src, name)
        dstname = os.path.join(dst, name)
        try:
            if symlinks and os.path.islink(srcname):
                linkto = os.readlink(srcname)
                os.symlink(linkto, dstname)
            elif os.path.isdir(srcname):
                copytree(srcname, dstname, symlinks, ignore)
            else:
                # Will raise a SpecialFileError for unsupported file types
                copy2(srcname, dstname)
        # catch the Error from the recursive copytree so that we can
        # continue with other files
        except Error, err:
            errors.extend(err.args[0])
        except EnvironmentError, why:
            errors.append((srcname, dstname, str(why)))
    try:
        copystat(src, dst)
    except OSError, why:
        if WindowsError is not None and isinstance(why, WindowsError):
            # Copying file access times may fail on Windows
            pass
        else:
            errors.append((src, dst, str(why)))
    if errors:
        raise Error, errors
shutil.copytree

⑧ shutil.rmtree(path[, ignore_errors[, onerror]]) 递归的去删除文件

技术分享
def rmtree(path, ignore_errors=False, onerror=None):
    """Recursively delete a directory tree.

    If ignore_errors is set, errors are ignored; otherwise, if onerror
    is set, it is called to handle the error with arguments (func,
    path, exc_info) where func is os.listdir, os.remove, or os.rmdir;
    path is the argument to that function that caused it to fail; and
    exc_info is a tuple returned by sys.exc_info().  If ignore_errors
    is false and onerror is None, an exception is raised.

    """
    if ignore_errors:
        def onerror(*args):
            pass
    elif onerror is None:
        def onerror(*args):
            raise
    try:
        if os.path.islink(path):
            # symlinks to directories are forbidden, see bug #1669
            raise OSError("Cannot call rmtree on a symbolic link")
    except OSError:
        onerror(os.path.islink, path, sys.exc_info())
        # can‘t continue even if onerror hook returns
        return
    names = []
    try:
        names = os.listdir(path)
    except os.error, err:
        onerror(os.listdir, path, sys.exc_info())
    for name in names:
        fullname = os.path.join(path, name)
        try:
            mode = os.lstat(fullname).st_mode
        except os.error:
            mode = 0
        if stat.S_ISDIR(mode):
            rmtree(fullname, ignore_errors, onerror)
        else:
            try:
                os.remove(fullname)
            except os.error, err:
                onerror(os.remove, fullname, sys.exc_info())
    try:
        os.rmdir(path)
    except os.error:
        onerror(os.rmdir, path, sys.exc_info())
shutil.rmtree

⑨ shutil.move(src, dst) 递归的去移动文件

技术分享
def move(src, dst):
    """Recursively move a file or directory to another location. This is
    similar to the Unix "mv" command.

    If the destination is a directory or a symlink to a directory, the source
    is moved inside the directory. The destination path must not already
    exist.

    If the destination already exists but is not a directory, it may be
    overwritten depending on os.rename() semantics.

    If the destination is on our current filesystem, then rename() is used.
    Otherwise, src is copied to the destination and then removed.
    A lot more could be done here...  A look at a mv.c shows a lot of
    the issues this implementation glosses over.

    """
    real_dst = dst
    if os.path.isdir(dst):
        if _samefile(src, dst):
            # We might be on a case insensitive filesystem,
            # perform the rename anyway.
            os.rename(src, dst)
            return

        real_dst = os.path.join(dst, _basename(src))
        if os.path.exists(real_dst):
            raise Error, "Destination path ‘%s‘ already exists" % real_dst
    try:
        os.rename(src, real_dst)
    except OSError:
        if os.path.isdir(src):
            if _destinsrc(src, dst):
                raise Error, "Cannot move a directory ‘%s‘ into itself ‘%s‘." % (src, dst)
            copytree(src, real_dst, symlinks=True)
            rmtree(src)
        else:
            copy2(src, real_dst)
            os.unlink(src)
shutil.move

⑩ shutil.make_archive(base_name, format,...) 创建压缩包并返回文件路径,例如:zip、tar

  • base_name: 压缩包的文件名,也可以是压缩包的路径。只是文件名时,则保存至当前目录,否则保存至指定路径,

        如:www                        =>保存至当前路径

        如:/Users/wupeiqi/www =>保存至/Users/wupeiqi/

  • format: 压缩包种类,“zip”, “tar”, “bztar”,“gztar”
  • root_dir: 要压缩的文件夹路径(默认当前目录)
  • owner: 用户,默认当前用户
  • group: 组,默认当前组
  • logger: 用于记录日志,通常是logging.Logger对象
技术分享
def make_archive(base_name, format, root_dir=None, base_dir=None, verbose=0,
                 dry_run=0, owner=None, group=None, logger=None):
    """Create an archive file (eg. zip or tar).

    ‘base_name‘ is the name of the file to create, minus any format-specific
    extension; ‘format‘ is the archive format: one of "zip", "tar", "bztar"
    or "gztar".

    ‘root_dir‘ is a directory that will be the root directory of the
    archive; ie. we typically chdir into ‘root_dir‘ before creating the
    archive.  ‘base_dir‘ is the directory where we start archiving from;
    ie. ‘base_dir‘ will be the common prefix of all files and
    directories in the archive.  ‘root_dir‘ and ‘base_dir‘ both default
    to the current directory.  Returns the name of the archive file.

    ‘owner‘ and ‘group‘ are used when creating a tar archive. By default,
    uses the current owner and group.
    """
    save_cwd = os.getcwd()
    if root_dir is not None:
        if logger is not None:
            logger.debug("changing into ‘%s‘", root_dir)
        base_name = os.path.abspath(base_name)
        if not dry_run:
            os.chdir(root_dir)

    if base_dir is None:
        base_dir = os.curdir

    kwargs = {dry_run: dry_run, logger: logger}

    try:
        format_info = _ARCHIVE_FORMATS[format]
    except KeyError:
        raise ValueError, "unknown archive format ‘%s‘" % format

    func = format_info[0]
    for arg, val in format_info[1]:
        kwargs[arg] = val

    if format != zip:
        kwargs[owner] = owner
        kwargs[group] = group

    try:
        filename = func(base_name, base_dir, **kwargs)
    finally:
        if root_dir is not None:
            if logger is not None:
                logger.debug("changing back to ‘%s‘", save_cwd)
            os.chdir(save_cwd)

    return filename
源码

shutil 对压缩包的处理是调用 ZipFile 和 TarFile 两个模块来进行的,详细:

技术分享
import zipfile

# 压缩
z = zipfile.ZipFile(laxi.zip, w)
z.write(a.log)
z.write(data.data)
z.close()

# 解压
z = zipfile.ZipFile(laxi.zip, r)
z.extractall()
z.close()

zipfile 压缩解压
zipfile 压缩解压
技术分享
import tarfile

# 压缩
tar = tarfile.open(your.tar,w)
tar.add(/Users/wupeiqi/PycharmProjects/bbs2.zip, arcname=bbs2.zip)
tar.add(/Users/wupeiqi/PycharmProjects/cmdb.zip, arcname=cmdb.zip)
tar.close()

# 解压
tar = tarfile.open(your.tar,r)
tar.extractall()  # 可设置解压地址
tar.close()

tarfile 压缩解压
tarfile 压缩解压
技术分享
class ZipFile(object):
    """ Class with methods to open, read, write, close, list zip files.

    z = ZipFile(file, mode="r", compression=ZIP_STORED, allowZip64=False)

    file: Either the path to the file, or a file-like object.
          If it is a path, the file will be opened and closed by ZipFile.
    mode: The mode can be either read "r", write "w" or append "a".
    compression: ZIP_STORED (no compression) or ZIP_DEFLATED (requires zlib).
    allowZip64: if True ZipFile will create files with ZIP64 extensions when
                needed, otherwise it will raise an exception when this would
                be necessary.

    """

    fp = None                   # Set here since __del__ checks it

    def __init__(self, file, mode="r", compression=ZIP_STORED, allowZip64=False):
        """Open the ZIP file with mode read "r", write "w" or append "a"."""
        if mode not in ("r", "w", "a"):
            raise RuntimeError(ZipFile() requires mode "r", "w", or "a")

        if compression == ZIP_STORED:
            pass
        elif compression == ZIP_DEFLATED:
            if not zlib:
                raise RuntimeError,                      "Compression requires the (missing) zlib module"
        else:
            raise RuntimeError, "That compression method is not supported"

        self._allowZip64 = allowZip64
        self._didModify = False
        self.debug = 0  # Level of printing: 0 through 3
        self.NameToInfo = {}    # Find file info given name
        self.filelist = []      # List of ZipInfo instances for archive
        self.compression = compression  # Method of compression
        self.mode = key = mode.replace(b, ‘‘)[0]
        self.pwd = None
        self._comment = ‘‘

        # Check if we were passed a file-like object
        if isinstance(file, basestring):
            self._filePassed = 0
            self.filename = file
            modeDict = {r : rb, w: wb, a : r+b}
            try:
                self.fp = open(file, modeDict[mode])
            except IOError:
                if mode == a:
                    mode = key = w
                    self.fp = open(file, modeDict[mode])
                else:
                    raise
        else:
            self._filePassed = 1
            self.fp = file
            self.filename = getattr(file, name, None)

        try:
            if key == r:
                self._RealGetContents()
            elif key == w:
                # set the modified flag so central directory gets written
                # even if no files are added to the archive
                self._didModify = True
            elif key == a:
                try:
                    # See if file is a zip file
                    self._RealGetContents()
                    # seek to start of directory and overwrite
                    self.fp.seek(self.start_dir, 0)
                except BadZipfile:
                    # file is not a zip file, just append
                    self.fp.seek(0, 2)

                    # set the modified flag so central directory gets written
                    # even if no files are added to the archive
                    self._didModify = True
            else:
                raise RuntimeError(Mode must be "r", "w" or "a")
        except:
            fp = self.fp
            self.fp = None
            if not self._filePassed:
                fp.close()
            raise

    def __enter__(self):
        return self

    def __exit__(self, type, value, traceback):
        self.close()

    def _RealGetContents(self):
        """Read in the table of contents for the ZIP file."""
        fp = self.fp
        try:
            endrec = _EndRecData(fp)
        except IOError:
            raise BadZipfile("File is not a zip file")
        if not endrec:
            raise BadZipfile, "File is not a zip file"
        if self.debug > 1:
            print endrec
        size_cd = endrec[_ECD_SIZE]             # bytes in central directory
        offset_cd = endrec[_ECD_OFFSET]         # offset of central directory
        self._comment = endrec[_ECD_COMMENT]    # archive comment

        # "concat" is zero, unless zip was concatenated to another file
        concat = endrec[_ECD_LOCATION] - size_cd - offset_cd
        if endrec[_ECD_SIGNATURE] == stringEndArchive64:
            # If Zip64 extension structures are present, account for them
            concat -= (sizeEndCentDir64 + sizeEndCentDir64Locator)

        if self.debug > 2:
            inferred = concat + offset_cd
            print "given, inferred, offset", offset_cd, inferred, concat
        # self.start_dir:  Position of start of central directory
        self.start_dir = offset_cd + concat
        fp.seek(self.start_dir, 0)
        data = fp.read(size_cd)
        fp = cStringIO.StringIO(data)
        total = 0
        while total < size_cd:
            centdir = fp.read(sizeCentralDir)
            if len(centdir) != sizeCentralDir:
                raise BadZipfile("Truncated central directory")
            centdir = struct.unpack(structCentralDir, centdir)
            if centdir[_CD_SIGNATURE] != stringCentralDir:
                raise BadZipfile("Bad magic number for central directory")
            if self.debug > 2:
                print centdir
            filename = fp.read(centdir[_CD_FILENAME_LENGTH])
            # Create ZipInfo instance to store file information
            x = ZipInfo(filename)
            x.extra = fp.read(centdir[_CD_EXTRA_FIELD_LENGTH])
            x.comment = fp.read(centdir[_CD_COMMENT_LENGTH])
            x.header_offset = centdir[_CD_LOCAL_HEADER_OFFSET]
            (x.create_version, x.create_system, x.extract_version, x.reserved,
                x.flag_bits, x.compress_type, t, d,
                x.CRC, x.compress_size, x.file_size) = centdir[1:12]
            x.volume, x.internal_attr, x.external_attr = centdir[15:18]
            # Convert date/time code to (year, month, day, hour, min, sec)
            x._raw_time = t
            x.date_time = ( (d>>9)+1980, (d>>5)&0xF, d&0x1F,
                                     t>>11, (t>>5)&0x3F, (t&0x1F) * 2 )

            x._decodeExtra()
            x.header_offset = x.header_offset + concat
            x.filename = x._decodeFilename()
            self.filelist.append(x)
            self.NameToInfo[x.filename] = x

            # update total bytes read from central directory
            total = (total + sizeCentralDir + centdir[_CD_FILENAME_LENGTH]
                     + centdir[_CD_EXTRA_FIELD_LENGTH]
                     + centdir[_CD_COMMENT_LENGTH])

            if self.debug > 2:
                print "total", total


    def namelist(self):
        """Return a list of file names in the archive."""
        l = []
        for data in self.filelist:
            l.append(data.filename)
        return l

    def infolist(self):
        """Return a list of class ZipInfo instances for files in the
        archive."""
        return self.filelist

    def printdir(self):
        """Print a table of contents for the zip file."""
        print "%-46s %19s %12s" % ("File Name", "Modified    ", "Size")
        for zinfo in self.filelist:
            date = "%d-%02d-%02d %02d:%02d:%02d" % zinfo.date_time[:6]
            print "%-46s %s %12d" % (zinfo.filename, date, zinfo.file_size)

    def testzip(self):
        """Read all the files and check the CRC."""
        chunk_size = 2 ** 20
        for zinfo in self.filelist:
            try:
                # Read by chunks, to avoid an OverflowError or a
                # MemoryError with very large embedded files.
                with self.open(zinfo.filename, "r") as f:
                    while f.read(chunk_size):     # Check CRC-32
                        pass
            except BadZipfile:
                return zinfo.filename

    def getinfo(self, name):
        """Return the instance of ZipInfo given ‘name‘."""
        info = self.NameToInfo.get(name)
        if info is None:
            raise KeyError(
                There is no item named %r in the archive % name)

        return info

    def setpassword(self, pwd):
        """Set default password for encrypted files."""
        self.pwd = pwd

    @property
    def comment(self):
        """The comment text associated with the ZIP file."""
        return self._comment

    @comment.setter
    def comment(self, comment):
        # check for valid comment length
        if len(comment) > ZIP_MAX_COMMENT:
            import warnings
            warnings.warn(Archive comment is too long; truncating to %d bytes
                          % ZIP_MAX_COMMENT, stacklevel=2)
            comment = comment[:ZIP_MAX_COMMENT]
        self._comment = comment
        self._didModify = True

    def read(self, name, pwd=None):
        """Return file bytes (as a string) for name."""
        return self.open(name, "r", pwd).read()

    def open(self, name, mode="r", pwd=None):
        """Return file-like object for ‘name‘."""
        if mode not in ("r", "U", "rU"):
            raise RuntimeError, open() requires mode "r", "U", or "rU"
        if not self.fp:
            raise RuntimeError,                   "Attempt to read ZIP archive that was already closed"

        # Only open a new file for instances where we were not
        # given a file object in the constructor
        if self._filePassed:
            zef_file = self.fp
            should_close = False
        else:
            zef_file = open(self.filename, rb)
            should_close = True

        try:
            # Make sure we have an info object
            if isinstance(name, ZipInfo):
                # ‘name‘ is already an info object
                zinfo = name
            else:
                # Get info object for name
                zinfo = self.getinfo(name)

            zef_file.seek(zinfo.header_offset, 0)

            # Skip the file header:
            fheader = zef_file.read(sizeFileHeader)
            if len(fheader) != sizeFileHeader:
                raise BadZipfile("Truncated file header")
            fheader = struct.unpack(structFileHeader, fheader)
            if fheader[_FH_SIGNATURE] != stringFileHeader:
                raise BadZipfile("Bad magic number for file header")

            fname = zef_file.read(fheader[_FH_FILENAME_LENGTH])
            if fheader[_FH_EXTRA_FIELD_LENGTH]:
                zef_file.read(fheader[_FH_EXTRA_FIELD_LENGTH])

            if fname != zinfo.orig_filename:
                raise BadZipfile,                         File name in directory "%s" and header "%s" differ. % (
                            zinfo.orig_filename, fname)

            # check for encrypted flag & handle password
            is_encrypted = zinfo.flag_bits & 0x1
            zd = None
            if is_encrypted:
                if not pwd:
                    pwd = self.pwd
                if not pwd:
                    raise RuntimeError, "File %s is encrypted, "                         "password required for extraction" % name

                zd = _ZipDecrypter(pwd)
                # The first 12 bytes in the cypher stream is an encryption header
                #  used to strengthen the algorithm. The first 11 bytes are
                #  completely random, while the 12th contains the MSB of the CRC,
                #  or the MSB of the file time depending on the header type
                #  and is used to check the correctness of the password.
                bytes = zef_file.read(12)
                h = map(zd, bytes[0:12])
                if zinfo.flag_bits & 0x8:
                    # compare against the file type from extended local headers
                    check_byte = (zinfo._raw_time >> 8) & 0xff
                else:
                    # compare against the CRC otherwise
                    check_byte = (zinfo.CRC >> 24) & 0xff
                if ord(h[11]) != check_byte:
                    raise RuntimeError("Bad password for file", name)

            return ZipExtFile(zef_file, mode, zinfo, zd,
                    close_fileobj=should_close)
        except:
            if should_close:
                zef_file.close()
            raise

    def extract(self, member, path=None, pwd=None):
        """Extract a member from the archive to the current working directory,
           using its full name. Its file information is extracted as accurately
           as possible. `member‘ may be a filename or a ZipInfo object. You can
           specify a different directory using `path‘.
        """
        if not isinstance(member, ZipInfo):
            member = self.getinfo(member)

        if path is None:
            path = os.getcwd()

        return self._extract_member(member, path, pwd)

    def extractall(self, path=None, members=None, pwd=None):
        """Extract all members from the archive to the current working
           directory. `path‘ specifies a different directory to extract to.
           `members‘ is optional and must be a subset of the list returned
           by namelist().
        """
        if members is None:
            members = self.namelist()

        for zipinfo in members:
            self.extract(zipinfo, path, pwd)

    def _extract_member(self, member, targetpath, pwd):
        """Extract the ZipInfo object ‘member‘ to a physical
           file on the path targetpath.
        """
        # build the destination pathname, replacing
        # forward slashes to platform specific separators.
        arcname = member.filename.replace(/, os.path.sep)

        if os.path.altsep:
            arcname = arcname.replace(os.path.altsep, os.path.sep)
        # interpret absolute pathname as relative, remove drive letter or
        # UNC path, redundant separators, "." and ".." components.
        arcname = os.path.splitdrive(arcname)[1]
        arcname = os.path.sep.join(x for x in arcname.split(os.path.sep)
                    if x not in (‘‘, os.path.curdir, os.path.pardir))
        if os.path.sep == \\\\:
            # filter illegal characters on Windows
            illegal = :<>|"?*
            if isinstance(arcname, unicode):
                table = {ord(c): ord(_) for c in illegal}
            else:
                table = string.maketrans(illegal, _ * len(illegal))
            arcname = arcname.translate(table)
            # remove trailing dots
            arcname = (x.rstrip(.) for x in arcname.split(os.path.sep))
            arcname = os.path.sep.join(x for x in arcname if x)

        targetpath = os.path.join(targetpath, arcname)
        targetpath = os.path.normpath(targetpath)

        # Create all upper directories if necessary.
        upperdirs = os.path.dirname(targetpath)
        if upperdirs and not os.path.exists(upperdirs):
            os.makedirs(upperdirs)

        if member.filename[-1] == /:
            if not os.path.isdir(targetpath):
                os.mkdir(targetpath)
            return targetpath

        with self.open(member, pwd=pwd) as source,              file(targetpath, "wb") as target:
            shutil.copyfileobj(source, target)

        return targetpath

    def _writecheck(self, zinfo):
        """Check for errors before writing a file to the archive."""
        if zinfo.filename in self.NameToInfo:
            import warnings
            warnings.warn(Duplicate name: %r % zinfo.filename, stacklevel=3)
        if self.mode not in ("w", "a"):
            raise RuntimeError, write() requires mode "w" or "a"
        if not self.fp:
            raise RuntimeError,                   "Attempt to write ZIP archive that was already closed"
        if zinfo.compress_type == ZIP_DEFLATED and not zlib:
            raise RuntimeError,                   "Compression requires the (missing) zlib module"
        if zinfo.compress_type not in (ZIP_STORED, ZIP_DEFLATED):
            raise RuntimeError,                   "That compression method is not supported"
        if not self._allowZip64:
            requires_zip64 = None
            if len(self.filelist) >= ZIP_FILECOUNT_LIMIT:
                requires_zip64 = "Files count"
            elif zinfo.file_size > ZIP64_LIMIT:
                requires_zip64 = "Filesize"
            elif zinfo.header_offset > ZIP64_LIMIT:
                requires_zip64 = "Zipfile size"
            if requires_zip64:
                raise LargeZipFile(requires_zip64 +
                                   " would require ZIP64 extensions")

    def write(self, filename, arcname=None, compress_type=None):
        """Put the bytes from filename into the archive under the name
        arcname."""
        if not self.fp:
            raise RuntimeError(
                  "Attempt to write to ZIP archive that was already closed")

        st = os.stat(filename)
        isdir = stat.S_ISDIR(st.st_mode)
        mtime = time.localtime(st.st_mtime)
        date_time = mtime[0:6]
        # Create ZipInfo instance to store file information
        if arcname is None:
            arcname = filename
        arcname = os.path.normpath(os.path.splitdrive(arcname)[1])
        while arcname[0] in (os.sep, os.altsep):
            arcname = arcname[1:]
        if isdir:
            arcname += /
        zinfo = ZipInfo(arcname, date_time)
        zinfo.external_attr = (st[0] & 0xFFFF) << 16L      # Unix attributes
        if compress_type is None:
            zinfo.compress_type = self.compression
        else:
            zinfo.compress_type = compress_type

        zinfo.file_size = st.st_size
        zinfo.flag_bits = 0x00
        zinfo.header_offset = self.fp.tell()    # Start of header bytes

        self._writecheck(zinfo)
        self._didModify = True

        if isdir:
            zinfo.file_size = 0
            zinfo.compress_size = 0
            zinfo.CRC = 0
            zinfo.external_attr |= 0x10  # MS-DOS directory flag
            self.filelist.append(zinfo)
            self.NameToInfo[zinfo.filename] = zinfo
            self.fp.write(zinfo.FileHeader(False))
            return

        with open(filename, "rb") as fp:
            # Must overwrite CRC and sizes with correct data later
            zinfo.CRC = CRC = 0
            zinfo.compress_size = compress_size = 0
            # Compressed size can be larger than uncompressed size
            zip64 = self._allowZip64 and                     zinfo.file_size * 1.05 > ZIP64_LIMIT
            self.fp.write(zinfo.FileHeader(zip64))
            if zinfo.compress_type == ZIP_DEFLATED:
                cmpr = zlib.compressobj(zlib.Z_DEFAULT_COMPRESSION,
                     zlib.DEFLATED, -15)
            else:
                cmpr = None
            file_size = 0
            while 1:
                buf = fp.read(1024 * 8)
                if not buf:
                    break
                file_size = file_size + len(buf)
                CRC = crc32(buf, CRC) & 0xffffffff
                if cmpr:
                    buf = cmpr.compress(buf)
                    compress_size = compress_size + len(buf)
                self.fp.write(buf)
        if cmpr:
            buf = cmpr.flush()
            compress_size = compress_size + len(buf)
            self.fp.write(buf)
            zinfo.compress_size = compress_size
        else:
            zinfo.compress_size = file_size
        zinfo.CRC = CRC
        zinfo.file_size = file_size
        if not zip64 and self._allowZip64:
            if file_size > ZIP64_LIMIT:
                raise RuntimeError(File size has increased during compressing)
            if compress_size > ZIP64_LIMIT:
                raise RuntimeError(Compressed size larger than uncompressed size)
        # Seek backwards and write file header (which will now include
        # correct CRC and file sizes)
        position = self.fp.tell()       # Preserve current position in file
        self.fp.seek(zinfo.header_offset, 0)
        self.fp.write(zinfo.FileHeader(zip64))
        self.fp.seek(position, 0)
        self.filelist.append(zinfo)
        self.NameToInfo[zinfo.filename] = zinfo

    def writestr(self, zinfo_or_arcname, bytes, compress_type=None):
        """Write a file into the archive.  The contents is the string
        ‘bytes‘.  ‘zinfo_or_arcname‘ is either a ZipInfo instance or
        the name of the file in the archive."""
        if not isinstance(zinfo_or_arcname, ZipInfo):
            zinfo = ZipInfo(filename=zinfo_or_arcname,
                            date_time=time.localtime(time.time())[:6])

            zinfo.compress_type = self.compression
            if zinfo.filename[-1] == /:
                zinfo.external_attr = 0o40775 << 16   # drwxrwxr-x
                zinfo.external_attr |= 0x10           # MS-DOS directory flag
            else:
                zinfo.external_attr = 0o600 << 16     # ?rw-------
        else:
            zinfo = zinfo_or_arcname

        if not self.fp:
            raise RuntimeError(
                  "Attempt to write to ZIP archive that was already closed")

        if compress_type is not None:
            zinfo.compress_type = compress_type

        zinfo.file_size = len(bytes)            # Uncompressed size
        zinfo.header_offset = self.fp.tell()    # Start of header bytes
        self._writecheck(zinfo)
        self._didModify = True
        zinfo.CRC = crc32(bytes) & 0xffffffff       # CRC-32 checksum
        if zinfo.compress_type == ZIP_DEFLATED:
            co = zlib.compressobj(zlib.Z_DEFAULT_COMPRESSION,
                 zlib.DEFLATED, -15)
            bytes = co.compress(bytes) + co.flush()
            zinfo.compress_size = len(bytes)    # Compressed size
        else:
            zinfo.compress_size = zinfo.file_size
        zip64 = zinfo.file_size > ZIP64_LIMIT or                 zinfo.compress_size > ZIP64_LIMIT
        if zip64 and not self._allowZip64:
            raise LargeZipFile("Filesize would require ZIP64 extensions")
        self.fp.write(zinfo.FileHeader(zip64))
        self.fp.write(bytes)
        if zinfo.flag_bits & 0x08:
            # Write CRC and file sizes after the file data
            fmt = <LQQ if zip64 else <LLL
            self.fp.write(struct.pack(fmt, zinfo.CRC, zinfo.compress_size,
                  zinfo.file_size))
        self.fp.flush()
        self.filelist.append(zinfo)
        self.NameToInfo[zinfo.filename] = zinfo

    def __del__(self):
        """Call the "close()" method in case the user forgot."""
        self.close()

    def close(self):
        """Close the file, and for mode "w" and "a" write the ending
        records."""
        if self.fp is None:
            return

        try:
            if self.mode in ("w", "a") and self._didModify: # write ending records
                pos1 = self.fp.tell()
                for zinfo in self.filelist:         # write central directory
                    dt = zinfo.date_time
                    dosdate = (dt[0] - 1980) << 9 | dt[1] << 5 | dt[2]
                    dostime = dt[3] << 11 | dt[4] << 5 | (dt[5] // 2)
                    extra = []
                    if zinfo.file_size > ZIP64_LIMIT                             or zinfo.compress_size > ZIP64_LIMIT:
                        extra.append(zinfo.file_size)
                        extra.append(zinfo.compress_size)
                        file_size = 0xffffffff
                        compress_size = 0xffffffff
                    else:
                        file_size = zinfo.file_size
                        compress_size = zinfo.compress_size

                    if zinfo.header_offset > ZIP64_LIMIT:
                        extra.append(zinfo.header_offset)
                        header_offset = 0xffffffffL
                    else:
                        header_offset = zinfo.header_offset

                    extra_data = zinfo.extra
                    if extra:
                        # Append a ZIP64 field to the extra‘s
                        extra_data = struct.pack(
                                <HH + Q*len(extra),
                                1, 8*len(extra), *extra) + extra_data

                        extract_version = max(45, zinfo.extract_version)
                        create_version = max(45, zinfo.create_version)
                    else:
                        extract_version = zinfo.extract_version
                        create_version = zinfo.create_version

                    try:
                        filename, flag_bits = zinfo._encodeFilenameFlags()
                        centdir = struct.pack(structCentralDir,
                        stringCentralDir, create_version,
                        zinfo.create_system, extract_version, zinfo.reserved,
                        flag_bits, zinfo.compress_type, dostime, dosdate,
                        zinfo.CRC, compress_size, file_size,
                        len(filename), len(extra_data), len(zinfo.comment),
                        0, zinfo.internal_attr, zinfo.external_attr,
                        header_offset)
                    except DeprecationWarning:
                        print >>sys.stderr, (structCentralDir,
                        stringCentralDir, create_version,
                        zinfo.create_system, extract_version, zinfo.reserved,
                        zinfo.flag_bits, zinfo.compress_type, dostime, dosdate,
                        zinfo.CRC, compress_size, file_size,
                        len(zinfo.filename), len(extra_data), len(zinfo.comment),
                        0, zinfo.internal_attr, zinfo.external_attr,
                        header_offset)
                        raise
                    self.fp.write(centdir)
                    self.fp.write(filename)
                    self.fp.write(extra_data)
                    self.fp.write(zinfo.comment)

                pos2 = self.fp.tell()
                # Write end-of-zip-archive record
                centDirCount = len(self.filelist)
                centDirSize = pos2 - pos1
                centDirOffset = pos1
                requires_zip64 = None
                if centDirCount > ZIP_FILECOUNT_LIMIT:
                    requires_zip64 = "Files count"
                elif centDirOffset > ZIP64_LIMIT:
                    requires_zip64 = "Central directory offset"
                elif centDirSize > ZIP64_LIMIT:
                    requires_zip64 = "Central directory size"
                if requires_zip64:
                    # Need to write the ZIP64 end-of-archive records
                    if not self._allowZip64:
                        raise LargeZipFile(requires_zip64 +
                                           " would require ZIP64 extensions")
                    zip64endrec = struct.pack(
                            structEndArchive64, stringEndArchive64,
                            44, 45, 45, 0, 0, centDirCount, centDirCount,
                            centDirSize, centDirOffset)
                    self.fp.write(zip64endrec)

                    zip64locrec = struct.pack(
                            structEndArchive64Locator,
                            stringEndArchive64Locator, 0, pos2, 1)
                    self.fp.write(zip64locrec)
                    centDirCount = min(centDirCount, 0xFFFF)
                    centDirSize = min(centDirSize, 0xFFFFFFFF)
                    centDirOffset = min(centDirOffset, 0xFFFFFFFF)

                endrec = struct.pack(structEndArchive, stringEndArchive,
                                    0, 0, centDirCount, centDirCount,
                                    centDirSize, centDirOffset, len(self._comment))
                self.fp.write(endrec)
                self.fp.write(self._comment)
                self.fp.flush()
        finally:
            fp = self.fp
            self.fp = None
            if not self._filePassed:
                fp.close()

ZipFile
ZipFile 源码
技术分享
class TarFile(object):
    """The TarFile Class provides an interface to tar archives.
    """

    debug = 0                   # May be set from 0 (no msgs) to 3 (all msgs)

    dereference = False         # If true, add content of linked file to the
                                # tar file, else the link.

    ignore_zeros = False        # If true, skips empty or invalid blocks and
                                # continues processing.

    errorlevel = 1              # If 0, fatal errors only appear in debug
                                # messages (if debug >= 0). If > 0, errors
                                # are passed to the caller as exceptions.

    format = DEFAULT_FORMAT     # The format to use when creating an archive.

    encoding = ENCODING         # Encoding for 8-bit character strings.

    errors = None               # Error handler for unicode conversion.

    tarinfo = TarInfo           # The default TarInfo class to use.

    fileobject = ExFileObject   # The default ExFileObject class to use.

    def __init__(self, name=None, mode="r", fileobj=None, format=None,
            tarinfo=None, dereference=None, ignore_zeros=None, encoding=None,
            errors=None, pax_headers=None, debug=None, errorlevel=None):
        """Open an (uncompressed) tar archive `name‘. `mode‘ is either ‘r‘ to
           read from an existing archive, ‘a‘ to append data to an existing
           file or ‘w‘ to create a new file overwriting an existing one. `mode‘
           defaults to ‘r‘.
           If `fileobj‘ is given, it is used for reading or writing data. If it
           can be determined, `mode‘ is overridden by `fileobj‘s mode.
           `fileobj‘ is not closed, when TarFile is closed.
        """
        modes = {"r": "rb", "a": "r+b", "w": "wb"}
        if mode not in modes:
            raise ValueError("mode must be ‘r‘, ‘a‘ or ‘w‘")
        self.mode = mode
        self._mode = modes[mode]

        if not fileobj:
            if self.mode == "a" and not os.path.exists(name):
                # Create nonexistent files in append mode.
                self.mode = "w"
                self._mode = "wb"
            fileobj = bltn_open(name, self._mode)
            self._extfileobj = False
        else:
            if name is None and hasattr(fileobj, "name"):
                name = fileobj.name
            if hasattr(fileobj, "mode"):
                self._mode = fileobj.mode
            self._extfileobj = True
        self.name = os.path.abspath(name) if name else None
        self.fileobj = fileobj

        # Init attributes.
        if format is not None:
            self.format = format
        if tarinfo is not None:
            self.tarinfo = tarinfo
        if dereference is not None:
            self.dereference = dereference
        if ignore_zeros is not None:
            self.ignore_zeros = ignore_zeros
        if encoding is not None:
            self.encoding = encoding

        if errors is not None:
            self.errors = errors
        elif mode == "r":
            self.errors = "utf-8"
        else:
            self.errors = "strict"

        if pax_headers is not None and self.format == PAX_FORMAT:
            self.pax_headers = pax_headers
        else:
            self.pax_headers = {}

        if debug is not None:
            self.debug = debug
        if errorlevel is not None:
            self.errorlevel = errorlevel

        # Init datastructures.
        self.closed = False
        self.members = []       # list of members as TarInfo objects
        self._loaded = False    # flag if all members have been read
        self.offset = self.fileobj.tell()
                                # current position in the archive file
        self.inodes = {}        # dictionary caching the inodes of
                                # archive members already added

        try:
            if self.mode == "r":
                self.firstmember = None
                self.firstmember = self.next()

            if self.mode == "a":
                # Move to the end of the archive,
                # before the first empty block.
                while True:
                    self.fileobj.seek(self.offset)
                    try:
                        tarinfo = self.tarinfo.fromtarfile(self)
                        self.members.append(tarinfo)
                    except EOFHeaderError:
                        self.fileobj.seek(self.offset)
                        break
                    except HeaderError, e:
                        raise ReadError(str(e))

            if self.mode in "aw":
                self._loaded = True

                if self.pax_headers:
                    buf = self.tarinfo.create_pax_global_header(self.pax_headers.copy())
                    self.fileobj.write(buf)
                    self.offset += len(buf)
        except:
            if not self._extfileobj:
                self.fileobj.close()
            self.closed = True
            raise

    def _getposix(self):
        return self.format == USTAR_FORMAT
    def _setposix(self, value):
        import warnings
        warnings.warn("use the format attribute instead", DeprecationWarning,
                      2)
        if value:
            self.format = USTAR_FORMAT
        else:
            self.format = GNU_FORMAT
    posix = property(_getposix, _setposix)

    #--------------------------------------------------------------------------
    # Below are the classmethods which act as alternate constructors to the
    # TarFile class. The open() method is the only one that is needed for
    # public use; it is the "super"-constructor and is able to select an
    # adequate "sub"-constructor for a particular compression using the mapping
    # from OPEN_METH.
    #
    # This concept allows one to subclass TarFile without losing the comfort of
    # the super-constructor. A sub-constructor is registered and made available
    # by adding it to the mapping in OPEN_METH.

    @classmethod
    def open(cls, name=None, mode="r", fileobj=None, bufsize=RECORDSIZE, **kwargs):
        """Open a tar archive for reading, writing or appending. Return
           an appropriate TarFile class.

           mode:
           ‘r‘ or ‘r:*‘ open for reading with transparent compression
           ‘r:‘         open for reading exclusively uncompressed
           ‘r:gz‘       open for reading with gzip compression
           ‘r:bz2‘      open for reading with bzip2 compression
           ‘a‘ or ‘a:‘  open for appending, creating the file if necessary
           ‘w‘ or ‘w:‘  open for writing without compression
           ‘w:gz‘       open for writing with gzip compression
           ‘w:bz2‘      open for writing with bzip2 compression

           ‘r|*‘        open a stream of tar blocks with transparent compression
           ‘r|‘         open an uncompressed stream of tar blocks for reading
           ‘r|gz‘       open a gzip compressed stream of tar blocks
           ‘r|bz2‘      open a bzip2 compressed stream of tar blocks
           ‘w|‘         open an uncompressed stream for writing
           ‘w|gz‘       open a gzip compressed stream for writing
           ‘w|bz2‘      open a bzip2 compressed stream for writing
        """

        if not name and not fileobj:
            raise ValueError("nothing to open")

        if mode in ("r", "r:*"):
            # Find out which *open() is appropriate for opening the file.
            for comptype in cls.OPEN_METH:
                func = getattr(cls, cls.OPEN_METH[comptype])
                if fileobj is not None:
                    saved_pos = fileobj.tell()
                try:
                    return func(name, "r", fileobj, **kwargs)
                except (ReadError, CompressionError), e:
                    if fileobj is not None:
                        fileobj.seek(saved_pos)
                    continue
            raise ReadError("file could not be opened successfully")

        elif ":" in mode:
            filemode, comptype = mode.split(":", 1)
            filemode = filemode or "r"
            comptype = comptype or "tar"

            # Select the *open() function according to
            # given compression.
            if comptype in cls.OPEN_METH:
                func = getattr(cls, cls.OPEN_METH[comptype])
            else:
                raise CompressionError("unknown compression type %r" % comptype)
            return func(name, filemode, fileobj, **kwargs)

        elif "|" in mode:
            filemode, comptype = mode.split("|", 1)
            filemode = filemode or "r"
            comptype = comptype or "tar"

            if filemode not in ("r", "w"):
                raise ValueError("mode must be ‘r‘ or ‘w‘")

            stream = _Stream(name, filemode, comptype, fileobj, bufsize)
            try:
                t = cls(name, filemode, stream, **kwargs)
            except:
                stream.close()
                raise
            t._extfileobj = False
            return t

        elif mode in ("a", "w"):
            return cls.taropen(name, mode, fileobj, **kwargs)

        raise ValueError("undiscernible mode")

    @classmethod
    def taropen(cls, name, mode="r", fileobj=None, **kwargs):
        """Open uncompressed tar archive name for reading or writing.
        """
        if mode not in ("r", "a", "w"):
            raise ValueError("mode must be ‘r‘, ‘a‘ or ‘w‘")
        return cls(name, mode, fileobj, **kwargs)

    @classmethod
    def gzopen(cls, name, mode="r", fileobj=None, compresslevel=9, **kwargs):
        """Open gzip compressed tar archive name for reading or writing.
           Appending is not allowed.
        """
        if mode not in ("r", "w"):
            raise ValueError("mode must be ‘r‘ or ‘w‘")

        try:
            import gzip
            gzip.GzipFile
        except (ImportError, AttributeError):
            raise CompressionError("gzip module is not available")

        try:
            fileobj = gzip.GzipFile(name, mode, compresslevel, fileobj)
        except OSError:
            if fileobj is not None and mode == r:
                raise ReadError("not a gzip file")
            raise

        try:
            t = cls.taropen(name, mode, fileobj, **kwargs)
        except IOError:
            fileobj.close()
            if mode == r:
                raise ReadError("not a gzip file")
            raise
        except:
            fileobj.close()
            raise
        t._extfileobj = False
        return t

    @classmethod
    def bz2open(cls, name, mode="r", fileobj=None, compresslevel=9, **kwargs):
        """Open bzip2 compressed tar archive name for reading or writing.
           Appending is not allowed.
        """
        if mode not in ("r", "w"):
            raise ValueError("mode must be ‘r‘ or ‘w‘.")

        try:
            import bz2
        except ImportError:
            raise CompressionError("bz2 module is not available")

        if fileobj is not None:
            fileobj = _BZ2Proxy(fileobj, mode)
        else:
            fileobj = bz2.BZ2File(name, mode, compresslevel=compresslevel)

        try:
            t = cls.taropen(name, mode, fileobj, **kwargs)
        except (IOError, EOFError):
            fileobj.close()
            if mode == r:
                raise ReadError("not a bzip2 file")
            raise
        except:
            fileobj.close()
            raise
        t._extfileobj = False
        return t

    # All *open() methods are registered here.
    OPEN_METH = {
        "tar": "taropen",   # uncompressed tar
        "gz":  "gzopen",    # gzip compressed tar
        "bz2": "bz2open"    # bzip2 compressed tar
    }

    #--------------------------------------------------------------------------
    # The public methods which TarFile provides:

    def close(self):
        """Close the TarFile. In write-mode, two finishing zero blocks are
           appended to the archive.
        """
        if self.closed:
            return

        if self.mode in "aw":
            self.fileobj.write(NUL * (BLOCKSIZE * 2))
            self.offset += (BLOCKSIZE * 2)
            # fill up the end with zero-blocks
            # (like option -b20 for tar does)
            blocks, remainder = divmod(self.offset, RECORDSIZE)
            if remainder > 0:
                self.fileobj.write(NUL * (RECORDSIZE - remainder))

        if not self._extfileobj:
            self.fileobj.close()
        self.closed = True

    def getmember(self, name):
        """Return a TarInfo object for member `name‘. If `name‘ can not be
           found in the archive, KeyError is raised. If a member occurs more
           than once in the archive, its last occurrence is assumed to be the
           most up-to-date version.
        """
        tarinfo = self._getmember(name)
        if tarinfo is None:
            raise KeyError("filename %r not found" % name)
        return tarinfo

    def getmembers(self):
        """Return the members of the archive as a list of TarInfo objects. The
           list has the same order as the members in the archive.
        """
        self._check()
        if not self._loaded:    # if we want to obtain a list of
            self._load()        # all members, we first have to
                                # scan the whole archive.
        return self.members

    def getnames(self):
        """Return the members of the archive as a list of their names. It has
           the same order as the list returned by getmembers().
        """
        return [tarinfo.name for tarinfo in self.getmembers()]

    def gettarinfo(self, name=None, arcname=None, fileobj=None):
        """Create a TarInfo object for either the file `name‘ or the file
           object `fileobj‘ (using os.fstat on its file descriptor). You can
           modify some of the TarInfo‘s attributes before you add it using
           addfile(). If given, `arcname‘ specifies an alternative name for the
           file in the archive.
        """
        self._check("aw")

        # When fileobj is given, replace name by
        # fileobj‘s real name.
        if fileobj is not None:
            name = fileobj.name

        # Building the name of the member in the archive.
        # Backward slashes are converted to forward slashes,
        # Absolute paths are turned to relative paths.
        if arcname is None:
            arcname = name
        drv, arcname = os.path.splitdrive(arcname)
        arcname = arcname.replace(os.sep, "/")
        arcname = arcname.lstrip("/")

        # Now, fill the TarInfo object with
        # information specific for the file.
        tarinfo = self.tarinfo()
        tarinfo.tarfile = self

        # Use os.stat or os.lstat, depending on platform
        # and if symlinks shall be resolved.
        if fileobj is None:
            if hasattr(os, "lstat") and not self.dereference:
                statres = os.lstat(name)
            else:
                statres = os.stat(name)
        else:
            statres = os.fstat(fileobj.fileno())
        linkname = ""

        stmd = statres.st_mode
        if stat.S_ISREG(stmd):
            inode = (statres.st_ino, statres.st_dev)
            if not self.dereference and statres.st_nlink > 1 and                     inode in self.inodes and arcname != self.inodes[inode]:
                # Is it a hardlink to an already
                # archived file?
                type = LNKTYPE
                linkname = self.inodes[inode]
            else:
                # The inode is added only if its valid.
                # For win32 it is always 0.
                type = REGTYPE
                if inode[0]:
                    self.inodes[inode] = arcname
        elif stat.S_ISDIR(stmd):
            type = DIRTYPE
        elif stat.S_ISFIFO(stmd):
            type = FIFOTYPE
        elif stat.S_ISLNK(stmd):
            type = SYMTYPE
            linkname = os.readlink(name)
        elif stat.S_ISCHR(stmd):
            type = CHRTYPE
        elif stat.S_ISBLK(stmd):
            type = BLKTYPE
        else:
            return None

        # Fill the TarInfo object with all
        # information we can get.
        tarinfo.name = arcname
        tarinfo.mode = stmd
        tarinfo.uid = statres.st_uid
        tarinfo.gid = statres.st_gid
        if type == REGTYPE:
            tarinfo.size = statres.st_size
        else:
            tarinfo.size = 0L
        tarinfo.mtime = statres.st_mtime
        tarinfo.type = type
        tarinfo.linkname = linkname
        if pwd:
            try:
                tarinfo.uname = pwd.getpwuid(tarinfo.uid)[0]
            except KeyError:
                pass
        if grp:
            try:
                tarinfo.gname = grp.getgrgid(tarinfo.gid)[0]
            except KeyError:
                pass

        if type in (CHRTYPE, BLKTYPE):
            if hasattr(os, "major") and hasattr(os, "minor"):
                tarinfo.devmajor = os.major(statres.st_rdev)
                tarinfo.devminor = os.minor(statres.st_rdev)
        return tarinfo

    def list(self, verbose=True):
        """Print a table of contents to sys.stdout. If `verbose‘ is False, only
           the names of the members are printed. If it is True, an `ls -l‘-like
           output is produced.
        """
        self._check()

        for tarinfo in self:
            if verbose:
                print filemode(tarinfo.mode),
                print "%s/%s" % (tarinfo.uname or tarinfo.uid,
                                 tarinfo.gname or tarinfo.gid),
                if tarinfo.ischr() or tarinfo.isblk():
                    print "%10s" % ("%d,%d"                                     % (tarinfo.devmajor, tarinfo.devminor)),
                else:
                    print "%10d" % tarinfo.size,
                print "%d-%02d-%02d %02d:%02d:%02d"                       % time.localtime(tarinfo.mtime)[:6],

            print tarinfo.name + ("/" if tarinfo.isdir() else ""),

            if verbose:
                if tarinfo.issym():
                    print "->", tarinfo.linkname,
                if tarinfo.islnk():
                    print "link to", tarinfo.linkname,
            print

    def add(self, name, arcname=None, recursive=True, exclude=None, filter=None):
        """Add the file `name‘ to the archive. `name‘ may be any type of file
           (directory, fifo, symbolic link, etc.). If given, `arcname‘
           specifies an alternative name for the file in the archive.
           Directories are added recursively by default. This can be avoided by
           setting `recursive‘ to False. `exclude‘ is a function that should
           return True for each filename to be excluded. `filter‘ is a function
           that expects a TarInfo object argument and returns the changed
           TarInfo object, if it returns None the TarInfo object will be
           excluded from the archive.
        """
        self._check("aw")

        if arcname is None:
            arcname = name

        # Exclude pathnames.
        if exclude is not None:
            import warnings
            warnings.warn("use the filter argument instead",
                    DeprecationWarning, 2)
            if exclude(name):
                self._dbg(2, "tarfile: Excluded %r" % name)
                return

        # Skip if somebody tries to archive the archive...
        if self.name is not None and os.path.abspath(name) == self.name:
            self._dbg(2, "tarfile: Skipped %r" % name)
            return

        self._dbg(1, name)

        # Create a TarInfo object from the file.
        tarinfo = self.gettarinfo(name, arcname)

        if tarinfo is None:
            self._dbg(1, "tarfile: Unsupported type %r" % name)
            return

        # Change or exclude the TarInfo object.
        if filter is not None:
            tarinfo = filter(tarinfo)
            if tarinfo is None:
                self._dbg(2, "tarfile: Excluded %r" % name)
                return

        # Append the tar header and data to the archive.
        if tarinfo.isreg():
            with bltn_open(name, "rb") as f:
                self.addfile(tarinfo, f)

        elif tarinfo.isdir():
            self.addfile(tarinfo)
            if recursive:
                for f in os.listdir(name):
                    self.add(os.path.join(name, f), os.path.join(arcname, f),
                            recursive, exclude, filter)

        else:
            self.addfile(tarinfo)

    def addfile(self, tarinfo, fileobj=None):
        """Add the TarInfo object `tarinfo‘ to the archive. If `fileobj‘ is
           given, tarinfo.size bytes are read from it and added to the archive.
           You can create TarInfo objects using gettarinfo().
           On Windows platforms, `fileobj‘ should always be opened with mode
           ‘rb‘ to avoid irritation about the file size.
        """
        self._check("aw")

        tarinfo = copy.copy(tarinfo)

        buf = tarinfo.tobuf(self.format, self.encoding, self.errors)
        self.fileobj.write(buf)
        self.offset += len(buf)

        # If there‘s data to follow, append it.
        if fileobj is not None:
            copyfileobj(fileobj, self.fileobj, tarinfo.size)
            blocks, remainder = divmod(tarinfo.size, BLOCKSIZE)
            if remainder > 0:
                self.fileobj.write(NUL * (BLOCKSIZE - remainder))
                blocks += 1
            self.offset += blocks * BLOCKSIZE

        self.members.append(tarinfo)

    def extractall(self, path=".", members=None):
        """Extract all members from the archive to the current working
           directory and set owner, modification time and permissions on
           directories afterwards. `path‘ specifies a different directory
           to extract to. `members‘ is optional and must be a subset of the
           list returned by getmembers().
        """
        directories = []

        if members is None:
            members = self

        for tarinfo in members:
            if tarinfo.isdir():
                # Extract directories with a safe mode.
                directories.append(tarinfo)
                tarinfo = copy.copy(tarinfo)
                tarinfo.mode = 0700
            self.extract(tarinfo, path)

        # Reverse sort directories.
        directories.sort(key=operator.attrgetter(name))
        directories.reverse()

        # Set correct owner, mtime and filemode on directories.
        for tarinfo in directories:
            dirpath = os.path.join(path, tarinfo.name)
            try:
                self.chown(tarinfo, dirpath)
                self.utime(tarinfo, dirpath)
                self.chmod(tarinfo, dirpath)
            except ExtractError, e:
                if self.errorlevel > 1:
                    raise
                else:
                    self._dbg(1, "tarfile: %s" % e)

    def extract(self, member, path=""):
        """Extract a member from the archive to the current working directory,
           using its full name. Its file information is extracted as accurately
           as possible. `member‘ may be a filename or a TarInfo object. You can
           specify a different directory using `path‘.
        """
        self._check("r")

        if isinstance(member, basestring):
            tarinfo = self.getmember(member)
        else:
            tarinfo = member

        # Prepare the link target for makelink().
        if tarinfo.islnk():
            tarinfo._link_target = os.path.join(path, tarinfo.linkname)

        try:
            self._extract_member(tarinfo, os.path.join(path, tarinfo.name))
        except EnvironmentError, e:
            if self.errorlevel > 0:
                raise
            else:
                if e.filename is None:
                    self._dbg(1, "tarfile: %s" % e.strerror)
                else:
                    self._dbg(1, "tarfile: %s %r" % (e.strerror, e.filename))
        except ExtractError, e:
            if self.errorlevel > 1:
                raise
            else:
                self._dbg(1, "tarfile: %s" % e)

    def extractfile(self, member):
        """Extract a member from the archive as a file object. `member‘ may be
           a filename or a TarInfo object. If `member‘ is a regular file, a
           file-like object is returned. If `member‘ is a link, a file-like
           object is constructed from the link‘s target. If `member‘ is none of
           the above, None is returned.
           The file-like object is read-only and provides the following
           methods: read(), readline(), readlines(), seek() and tell()
        """
        self._check("r")

        if isinstance(member, basestring):
            tarinfo = self.getmember(member)
        else:
            tarinfo = member

        if tarinfo.isreg():
            return self.fileobject(self, tarinfo)

        elif tarinfo.type not in SUPPORTED_TYPES:
            # If a member‘s type is unknown, it is treated as a
            # regular file.
            return self.fileobject(self, tarinfo)

        elif tarinfo.islnk() or tarinfo.issym():
            if isinstance(self.fileobj, _Stream):
                # A small but ugly workaround for the case that someone tries
                # to extract a (sym)link as a file-object from a non-seekable
                # stream of tar blocks.
                raise StreamError("cannot extract (sym)link as file object")
            else:
                # A (sym)link‘s file object is its target‘s file object.
                return self.extractfile(self._find_link_target(tarinfo))
        else:
            # If there‘s no data associated with the member (directory, chrdev,
            # blkdev, etc.), return None instead of a file object.
            return None

    def _extract_member(self, tarinfo, targetpath):
        """Extract the TarInfo object tarinfo to a physical
           file called targetpath.
        """
        # Fetch the TarInfo object for the given name
        # and build the destination pathname, replacing
        # forward slashes to platform specific separators.
        targetpath = targetpath.rstrip("/")
        targetpath = targetpath.replace("/", os.sep)

        # Create all upper directories.
        upperdirs = os.path.dirname(targetpath)
        if upperdirs and not os.path.exists(upperdirs):
            # Create directories that are not part of the archive with
            # default permissions.
            os.makedirs(upperdirs)

        if tarinfo.islnk() or tarinfo.issym():
            self._dbg(1, "%s -> %s" % (tarinfo.name, tarinfo.linkname))
        else:
            self._dbg(1, tarinfo.name)

        if tarinfo.isreg():
            self.makefile(tarinfo, targetpath)
        elif tarinfo.isdir():
            self.makedir(tarinfo, targetpath)
        elif tarinfo.isfifo():
            self.makefifo(tarinfo, targetpath)
        elif tarinfo.ischr() or tarinfo.isblk():
            self.makedev(tarinfo, targetpath)
        elif tarinfo.islnk() or tarinfo.issym():
            self.makelink(tarinfo, targetpath)
        elif tarinfo.type not in SUPPORTED_TYPES:
            self.makeunknown(tarinfo, targetpath)
        else:
            self.makefile(tarinfo, targetpath)

        self.chown(tarinfo, targetpath)
        if not tarinfo.issym():
            self.chmod(tarinfo, targetpath)
            self.utime(tarinfo, targetpath)

    #--------------------------------------------------------------------------
    # Below are the different file methods. They are called via
    # _extract_member() when extract() is called. They can be replaced in a
    # subclass to implement other functionality.

    def makedir(self, tarinfo, targetpath):
        """Make a directory called targetpath.
        """
        try:
            # Use a safe mode for the directory, the real mode is set
            # later in _extract_member().
            os.mkdir(targetpath, 0700)
        except EnvironmentError, e:
            if e.errno != errno.EEXIST:
                raise

    def makefile(self, tarinfo, targetpath):
        """Make a file called targetpath.
        """
        source = self.extractfile(tarinfo)
        try:
            with bltn_open(targetpath, "wb") as target:
                copyfileobj(source, target)
        finally:
            source.close()

    def makeunknown(self, tarinfo, targetpath):
        """Make a file from a TarInfo object with an unknown type
           at targetpath.
        """
        self.makefile(tarinfo, targetpath)
        self._dbg(1, "tarfile: Unknown file type %r, "                      "extracted as regular file." % tarinfo.type)

    def makefifo(self, tarinfo, targetpath):
        """Make a fifo called targetpath.
        """
        if hasattr(os, "mkfifo"):
            os.mkfifo(targetpath)
        else:
            raise ExtractError("fifo not supported by system")

    def makedev(self, tarinfo, targetpath):
        """Make a character or block device called targetpath.
        """
        if not hasattr(os, "mknod") or not hasattr(os, "makedev"):
            raise ExtractError("special devices not supported by system")

        mode = tarinfo.mode
        if tarinfo.isblk():
            mode |= stat.S_IFBLK
        else:
            mode |= stat.S_IFCHR

        os.mknod(targetpath, mode,
                 os.makedev(tarinfo.devmajor, tarinfo.devminor))

    def makelink(self, tarinfo, targetpath):
        """Make a (symbolic) link called targetpath. If it cannot be created
          (platform limitation), we try to make a copy of the referenced file
          instead of a link.
        """
        if hasattr(os, "symlink") and hasattr(os, "link"):
            # For systems that support symbolic and hard links.
            if tarinfo.issym():
                if os.path.lexists(targetpath):
                    os.unlink(targetpath)
                os.symlink(tarinfo.linkname, targetpath)
            else:
                # See extract().
                if os.path.exists(tarinfo._link_target):
                    if os.path.lexists(targetpath):
                        os.unlink(targetpath)
                    os.link(tarinfo._link_target, targetpath)
                else:
                    self._extract_member(self._find_link_target(tarinfo), targetpath)
        else:
            try:
                self._extract_member(self._find_link_target(tarinfo), targetpath)
            except KeyError:
                raise ExtractError("unable to resolve link inside archive")

    def chown(self, tarinfo, targetpath):
        """Set owner of targetpath according to tarinfo.
        """
        if pwd and hasattr(os, "geteuid") and os.geteuid() == 0:
            # We have to be root to do so.
            try:
                g = grp.getgrnam(tarinfo.gname)[2]
            except KeyError:
                g = tarinfo.gid
            try:
                u = pwd.getpwnam(tarinfo.uname)[2]
            except KeyError:
                u = tarinfo.uid
            try:
                if tarinfo.issym() and hasattr(os, "lchown"):
                    os.lchown(targetpath, u, g)
                else:
                    if sys.platform != "os2emx":
                        os.chown(targetpath, u, g)
            except EnvironmentError, e:
                raise ExtractError("could not change owner")

    def chmod(self, tarinfo, targetpath):
        """Set file permissions of targetpath according to tarinfo.
        """
        if hasattr(os, chmod):
            try:
                os.chmod(targetpath, tarinfo.mode)
            except EnvironmentError, e:
                raise ExtractError("could not change mode")

    def utime(self, tarinfo, targetpath):
        """Set modification time of targetpath according to tarinfo.
        """
        if not hasattr(os, utime):
            return
        try:
            os.utime(targetpath, (tarinfo.mtime, tarinfo.mtime))
        except EnvironmentError, e:
            raise ExtractError("could not change modification time")

    #--------------------------------------------------------------------------
    def next(self):
        """Return the next member of the archive as a TarInfo object, when
           TarFile is opened for reading. Return None if there is no more
           available.
        """
        self._check("ra")
        if self.firstmember is not None:
            m = self.firstmember
            self.firstmember = None
            return m

        # Read the next block.
        self.fileobj.seek(self.offset)
        tarinfo = None
        while True:
            try:
                tarinfo = self.tarinfo.fromtarfile(self)
            except EOFHeaderError, e:
                if self.ignore_zeros:
                    self._dbg(2, "0x%X: %s" % (self.offset, e))
                    self.offset += BLOCKSIZE
                    continue
            except InvalidHeaderError, e:
                if self.ignore_zeros:
                    self._dbg(2, "0x%X: %s" % (self.offset, e))
                    self.offset += BLOCKSIZE
                    continue
                elif self.offset == 0:
                    raise ReadError(str(e))
            except EmptyHeaderError:
                if self.offset == 0:
                    raise ReadError("empty file")
            except TruncatedHeaderError, e:
                if self.offset == 0:
                    raise ReadError(str(e))
            except SubsequentHeaderError, e:
                raise ReadError(str(e))
            break

        if tarinfo is not None:
            self.members.append(tarinfo)
        else:
            self._loaded = True

        return tarinfo

    #--------------------------------------------------------------------------
    # Little helper methods:

    def _getmember(self, name, tarinfo=None, normalize=False):
        """Find an archive member by name from bottom to top.
           If tarinfo is given, it is used as the starting point.
        """
        # Ensure that all members have been loaded.
        members = self.getmembers()

        # Limit the member search list up to tarinfo.
        if tarinfo is not None:
            members = members[:members.index(tarinfo)]

        if normalize:
            name = os.path.normpath(name)

        for member in reversed(members):
            if normalize:
                member_name = os.path.normpath(member.name)
            else:
                member_name = member.name

            if name == member_name:
                return member

    def _load(self):
        """Read through the entire archive file and look for readable
           members.
        """
        while True:
            tarinfo = self.next()
            if tarinfo is None:
                break
        self._loaded = True

    def _check(self, mode=None):
        """Check if TarFile is still open, and if the operation‘s mode
           corresponds to TarFile‘s mode.
        """
        if self.closed:
            raise IOError("%s is closed" % self.__class__.__name__)
        if mode is not None and self.mode not in mode:
            raise IOError("bad operation for mode %r" % self.mode)

    def _find_link_target(self, tarinfo):
        """Find the target member of a symlink or hardlink member in the
           archive.
        """
        if tarinfo.issym():
            # Always search the entire archive.
            linkname = "/".join(filter(None, (os.path.dirname(tarinfo.name), tarinfo.linkname)))
            limit = None
        else:
            # Search the archive before the link, because a hard link is
            # just a reference to an already archived file.
            linkname = tarinfo.linkname
            limit = tarinfo

        member = self._getmember(linkname, tarinfo=limit, normalize=True)
        if member is None:
            raise KeyError("linkname %r not found" % linkname)
        return member

    def __iter__(self):
        """Provide an iterator object.
        """
        if self._loaded:
            return iter(self.members)
        else:
            return TarIter(self)

    def _dbg(self, level, msg):
        """Write debugging output to sys.stderr.
        """
        if level <= self.debug:
            print >> sys.stderr, msg

    def __enter__(self):
        self._check()
        return self

    def __exit__(self, type, value, traceback):
        if type is None:
            self.close()
        else:
            # An exception occurred. We must not call close() because
            # it would try to write end-of-archive blocks and padding.
            if not self._extfileobj:
                self.fileobj.close()
            self.closed = True
# class TarFile

TarFile
TarFile 源码

 

6、json 和 pickle模块

文件只能存二进制或字符串,不能存其他类型,所以用到了用于序列化的两个模块:

json,用于字符串和python数据类型间进行转换,将数据通过特殊的形式转换为所有语言都认识的字符串(字典,变量,列表)

pickle,用于python特有的类型和python的数据类型间进行转换,将数据通过特殊的形式转换为只有python认识的字符串(函数,类)

json模块:

#json 序列化和反序列化
import json

info ={               #字典
    "name":"lzl",
    "age":"18"
}

with open("test","w") as f:
    f.write(json.dumps(info))   #用json把info写入到文件test中

with open("test","r") as f:
    info = json.loads(f.read())
    print(info["name"])

#lzl

② pickle模块:

#pickle 序列化和反序列化
import pickle        #pickle支持python特有的所有类型

def func():                 #函数
    info ={
        "name":"lzl",
        "age":"18"
    }
    print(info,type(info))

func()
#{‘age‘: ‘18‘, ‘name‘: ‘lzl‘} <class ‘dict‘>

with open("test","wb") as f:
    f.write(pickle.dumps(func))   #用pickle把func写入到文件test中 如果用json此时会报错

with open("test","rb") as f:
    func_new = pickle.loads(f.read())
    func_new()
#{‘age‘: ‘18‘, ‘name‘: ‘lzl‘} <class ‘dict‘>

更多内容-》》http://openskill.cn/article/472

 

7、shelve模块

shelve模块内部对pickle进行了封装,shelve模块是一个简单的k,v将内存数据通过文件持久化的模块,可以持久化任何pickle可支持的python数据格式

#!/usr/bin/env python
# -*- coding:utf-8 -*-
#-Author-Lian

import shelve

# k,v方式存储数据
s = shelve.open("shelve_test")  # 打开一个文件
tuple = (1, 2, 3, 4)
list = [‘a‘, ‘b‘, ‘c‘, ‘d‘]
info = {"name": "lzl", "age": 18}
s["tuple"] = tuple  # 持久化元组
s["list"] = list
s["info"] = info
s.close()


# 通过key获取value值
d = shelve.open("shelve_test")  # 打开一个文件
print(d["tuple"])  # 读取
print(d.get("list"))
print(d.get("info"))

# (1, 2, 3, 4)
# [‘a‘, ‘b‘, ‘c‘, ‘d‘]
# {‘name‘: ‘lzl‘, ‘age‘: 18}
d.close()


# 循环打印key值
s = shelve.open("shelve_test")  # 打开一个文件
for k in s.keys():              # 循环key值
    print(k)

# list
# tuple
# info
s.close()


# 更新key的value值
s = shelve.open("shelve_test")  # 打开一个文件
s.update({"list":[22,33]})      #重新赋值或者s["list"] = [22,33]
print(s["list"])

#[22, 33]
s.close()

 

8、xml模块

xml是实现不同语言或程序之间进行数据交换的协议,跟json差不多,但json使用起来更简单,不过,古时候,在json还没诞生的黑暗年代,大家只能选择用xml呀,至今很多传统公司如金融行业的很多系统的接口还主要是xml

xml的格式如下,就是通过<>节点来区别数据结构的:

技术分享
<?xml version="1.0"?>
<data>
    <country name="Liechtenstein">
        <rank updated="yes">2</rank>
        <year>2008</year>
        <gdppc>141100</gdppc>
        <neighbor name="Austria" direction="E"/>
        <neighbor name="Switzerland" direction="W"/>
    </country>
    <country name="Singapore">
        <rank updated="yes">5</rank>
        <year>2011</year>
        <gdppc>59900</gdppc>
        <neighbor name="Malaysia" direction="N"/>
    </country>
    <country name="Panama">
        <rank updated="yes">69</rank>
        <year>2011</year>
        <gdppc>13600</gdppc>
        <neighbor name="Costa Rica" direction="W"/>
        <neighbor name="Colombia" direction="E"/>
    </country>
</data>
xml格式

xml协议在各个语言里的都是支持的,在python中可以用以下模块操作xml  

import xml.etree.ElementTree as ET
 
tree = ET.parse("xmltest.xml")
root = tree.getroot()
print(root.tag)
 
#遍历xml文档
for child in root:
    print(child.tag, child.attrib)
    for i in child:
        print(i.tag,i.text)
 
#只遍历year 节点
for node in root.iter(‘year‘):
    print(node.tag,node.text)

修改和删除xml文档内容

import xml.etree.ElementTree as ET
 
tree = ET.parse("xmltest.xml")
root = tree.getroot()
 
#修改
for node in root.iter(‘year‘):
    new_year = int(node.text) + 1
    node.text = str(new_year)
    node.set("updated","yes")
 
tree.write("xmltest.xml")
 
 
#删除node
for country in root.findall(‘country‘):
   rank = int(country.find(‘rank‘).text)
   if rank > 50:
     root.remove(country)
 
tree.write(‘output.xml‘)

自己创建xml文档

import xml.etree.ElementTree as ET
 
 
new_xml = ET.Element("namelist")
name = ET.SubElement(new_xml,"name",attrib={"enrolled":"yes"})
age = ET.SubElement(name,"age",attrib={"checked":"no"})
sex = ET.SubElement(name,"sex")
sex.text = ‘33‘
name2 = ET.SubElement(new_xml,"name",attrib={"enrolled":"no"})
age = ET.SubElement(name2,"age")
age.text = ‘19‘
 
et = ET.ElementTree(new_xml) #生成文档对象
et.write("test.xml", encoding="utf-8",xml_declaration=True)
 
ET.dump(new_xml) #打印生成的格式

 

9、configparser模块

用于生成和修改常见配置文档,当前模块的名称在 python 3.x 版本中变更为 configparser

来看一个好多软件的常见文档格式如下:

技术分享
[DEFAULT]
ServerAliveInterval = 45
Compression = yes
CompressionLevel = 9
ForwardX11 = yes
 
[bitbucket.org]
User = hg
 
[topsecret.server.com]
Port = 50022
ForwardX11 = no
配置文件

如果想用python生成一个这样的文档怎么做呢?

import configparser
 
config = configparser.ConfigParser()
config["DEFAULT"] = {‘ServerAliveInterval‘: ‘45‘,
                      ‘Compression‘: ‘yes‘,
                     ‘CompressionLevel‘: ‘9‘}
 
config[‘bitbucket.org‘] = {}
config[‘bitbucket.org‘][‘User‘] = ‘hg‘
config[‘topsecret.server.com‘] = {}
topsecret = config[‘topsecret.server.com‘]
topsecret[‘Host Port‘] = ‘50022‘     # mutates the parser
topsecret[‘ForwardX11‘] = ‘no‘  # same here
config[‘DEFAULT‘][‘ForwardX11‘] = ‘yes‘
with open(‘example.ini‘, ‘w‘) as configfile:
   config.write(configfile)

写完了还可以再读出来哈:

>>> import configparser
>>> config = configparser.ConfigParser()
>>> config.sections()
[]
>>> config.read(‘example.ini‘)
[‘example.ini‘]
>>> config.sections()
[‘bitbucket.org‘, ‘topsecret.server.com‘]
>>> ‘bitbucket.org‘ in config
True
>>> ‘bytebong.com‘ in config
False
>>> config[‘bitbucket.org‘][‘User‘]
‘hg‘
>>> config[‘DEFAULT‘][‘Compression‘]
‘yes‘
>>> topsecret = config[‘topsecret.server.com‘]
>>> topsecret[‘ForwardX11‘]
‘no‘
>>> topsecret[‘Port‘]
‘50022‘
>>> for key in config[‘bitbucket.org‘]: print(key)
...
user
compressionlevel
serveraliveinterval
compression
forwardx11
>>> config[‘bitbucket.org‘][‘ForwardX11‘]
‘yes‘

configparser增删改查语法:

[section1]
k1 = v1
k2:v2
  
[section2]
k1 = v1
 
import ConfigParser
  
config = ConfigParser.ConfigParser()
config.read(‘i.cfg‘)
  
# ########## 读 ##########
#secs = config.sections()
#print secs
#options = config.options(‘group2‘)
#print options
  
#item_list = config.items(‘group2‘)
#print item_list
  
#val = config.get(‘group1‘,‘key‘)
#val = config.getint(‘group1‘,‘key‘)
  
# ########## 改写 ##########
#sec = config.remove_section(‘group1‘)
#config.write(open(‘i.cfg‘, "w"))
  
#sec = config.has_section(‘wupeiqi‘)
#sec = config.add_section(‘wupeiqi‘)
#config.write(open(‘i.cfg‘, "w"))
  
  
#config.set(‘group2‘,‘k1‘,11111)
#config.write(open(‘i.cfg‘, "w"))
  
#config.remove_option(‘group2‘,‘age‘)
#config.write(open(‘i.cfg‘, "w"))

 

10、hashlib模块 

用于加密相关的操作,3.x里代替了md5模块和sha模块,主要提供 SHA1, SHA224, SHA256, SHA384, SHA512 ,MD5 算法

import hashlib
 
m = hashlib.md5()
m.update(b"Hello")
m.update(b"It‘s me")
print(m.digest())
m.update(b"It‘s been a long time since last time we ...")
 
print(m.digest()) #2进制格式hash
print(len(m.hexdigest())) #16进制格式hash
‘‘‘
def digest(self, *args, **kwargs): # real signature unknown
    """ Return the digest value as a string of binary data. """
    pass
 
def hexdigest(self, *args, **kwargs): # real signature unknown
    """ Return the digest value as a string of hexadecimal digits. """
    pass
 
‘‘‘
import hashlib
 
# ######## md5 ########
 
hash = hashlib.md5()
hash.update(‘admin‘)
print(hash.hexdigest())
 
# ######## sha1 ########
 
hash = hashlib.sha1()
hash.update(‘admin‘)
print(hash.hexdigest())
 
# ######## sha256 ########
 
hash = hashlib.sha256()
hash.update(‘admin‘)
print(hash.hexdigest())
 
 
# ######## sha384 ########
 
hash = hashlib.sha384()
hash.update(‘admin‘)
print(hash.hexdigest())
 
# ######## sha512 ########
 
hash = hashlib.sha512()
hash.update(‘admin‘)
print(hash.hexdigest())

还不够吊?python 还有一个 hmac 模块,它内部对我们创建 key 和 内容 再进行处理然后再加密

import hmac
h = hmac.new(‘wueiqi‘)
h.update(‘hellowo‘)
print h.hexdigest()

  

11、re模块

re模块用于对python的正则表达式的操作

‘.‘     默认匹配除\\n之外的任意一个字符,若指定flag DOTALL,则匹配任意字符,包括换行
‘^‘     匹配字符开头,若指定flags MULTILINE,这种也可以匹配上(r"^a","\\nabc\\neee",flags=re.MULTILINE)
‘$‘     匹配字符结尾,或e.search("foo$","bfoo\\nsdfsf",flags=re.MULTILINE).group()也可以
‘*‘     匹配*号前的字符0次或多次,re.findall("ab*","cabb3abcbbac")  结果为[‘abb‘, ‘ab‘, ‘a‘]
‘+‘     匹配前一个字符1次或多次,re.findall("ab+","ab+cd+abb+bba") 结果[‘ab‘, ‘abb‘]
‘?‘     匹配前一个字符1次或0次
‘{m}‘   匹配前一个字符m次
‘{n,m}‘ 匹配前一个字符n到m次,re.findall("ab{1,3}","abb abc abbcbbb") 结果‘abb‘, ‘ab‘, ‘abb‘]
‘|‘     匹配|左或|右的字符,re.search("abc|ABC","ABCBabcCD").group() 结果‘ABC‘
‘(...)‘ 分组匹配,re.search("(abc){2}a(123|456)c", "abcabca456c").group() 结果 abcabca456c
‘[a-z]‘ 匹配a到z任意一个字符
‘[^()]‘ 匹配除()以外的任意一个字符 

r‘ ‘    转义引号里的字符 针对\\字符  详情查看⑦
‘\\A‘    只从字符开头匹配,re.search("\\Aabc","alexabc") 是匹配不到的
‘\\Z‘    匹配字符结尾,同$
‘\\d‘    匹配数字0-9
‘\\D‘    匹配非数字
‘\\w‘    匹配[A-Za-z0-9]
‘\\W‘    匹配非[A-Za-z0-9]
‘\\s‘    匹配空白字符、\\t、\\n、\\r , re.search("\\s+","ab\\tc1\\n3").group() 结果 ‘\\t‘
  
‘(?P<name>...)‘ 分组匹配 re.search("(?P<province>[0-9]{4})(?P<city>[0-9]{2})(?P<birthday>[0-9]{4})","371481199306143242").groupdict("city")
结果{‘province‘: ‘3714‘, ‘city‘: ‘81‘, ‘birthday‘: ‘1993‘}

 标志位:

技术分享
# flags
I = IGNORECASE = sre_compile.SRE_FLAG_IGNORECASE # ignore case
L = LOCALE = sre_compile.SRE_FLAG_LOCALE # assume current 8-bit locale
U = UNICODE = sre_compile.SRE_FLAG_UNICODE # assume unicode locale
M = MULTILINE = sre_compile.SRE_FLAG_MULTILINE # make anchors look for newline
S = DOTALL = sre_compile.SRE_FLAG_DOTALL # make dot match newline
X = VERBOSE = sre_compile.SRE_FLAG_VERBOSE # ignore whitespace and comments

flags
flags

、match

从起始位置开始根据模型去字符串中匹配指定内容:

#match
import re                               

obj = re.match(‘\\d+‘, ‘123uua123sf‘)       #从第一个字符开始匹配一个到多个数字
print(obj)                                
#<_sre.SRE_Match object; span=(0, 3), match=‘123‘>

if obj:                                   #如果有匹配到字符则执行,为空不执行
    print(obj.group())                    #打印匹配到的内容
#123

匹配ip地址:

import re

ip = ‘255.255.255.253‘
result=re.match(r‘^([1-9]?\\d|1\\d\\d|2[0-4]\\d|25[0-5])\\.([1-9]?\\d|1\\d\\d|2[0-4]\\d|25[0-5])\\.‘
                r‘([1-9]?\\d|1\\d\\d|2[0-4]\\d|25[0-5])\\.([1-9]?\\d|1\\d\\d|2[0-4]\\d|25[0-5])$‘,ip)
print(result)
# <_sre.SRE_Match object; span=(0, 15), match=‘255.255.255.253‘>

、search

根据模型去字符串中匹配指定内容(不一定是最开始位置),匹配最前

#search
import  re
obj = re.search(‘\\d+‘, ‘a123uu234asf‘)     #从数字开始匹配一个到多个数字
print(obj)
#<_sre.SRE_Match object; span=(1, 4), match=‘123‘>

if obj:                                   #如果有匹配到字符则执行,为空不执行
    print(obj.group())                    #打印匹配到的内容
#123


import  re
obj = re.search(‘\\([^()]+\\)‘, ‘sdds(a1fwewe2(3uusfdsf2)34as)f‘)     #匹配最里面()的内容
print(obj)
#<_sre.SRE_Match object; span=(13, 24), match=‘(3uusfdsf2)‘>

if obj:                                   #如果有匹配到字符则执行,为空不执行
    print(obj.group())                    #打印匹配到的内容
#(3uusfdsf2)

、group与groups的区别

#group与groups的区别
import  re
a = "123abc456"
b = re.search("([0-9]*)([a-z]*)([0-9]*)", a)
print(b)
#<_sre.SRE_Match object; span=(0, 9), match=‘123abc456‘>
print(b.group())
#123abc456
print(b.group(0))
#123abc456
print(b.group(1))
#123
print(b.group(2))
#abc
print(b.group(3))
#456
print(b.groups())
#(‘123‘, ‘abc‘, ‘456‘)

findall

上述两中方式均用于匹配单值,即:只能匹配字符串中的一个,如果想要匹配到字符串中所有符合条件的元素,则需要使用 findall;findall没有group用法

#findall
import  re
obj = re.findall(‘\\d+‘, ‘a123uu234asf‘)     #匹配多个

if obj:                                   #如果有匹配到字符则执行,为空不执行
    print(obj)                             #生成的内容为列表
#[‘123‘, ‘234‘]

、sub

用于替换匹配的字符串(pattern, repl, string, count=0, flags=0)

#sub
import  re

content = "123abc456"
new_content = re.sub(‘\\d+‘, ‘ABC‘, content)
print(new_content)
#ABCabcABC

、split

根据指定匹配进行分组(pattern, string, maxsplit=0, flags=0)

#split
import  re

content = "1 - 2 * ((60-30+1*(9-2*5/3+7/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2) )"
new_content = re.split(‘\\*‘, content)       #用*进行分割,分割为列表
print(new_content)
#[‘1 - 2 ‘, ‘ ((60-30+1‘, ‘(9-2‘, ‘5/3+7/3‘, ‘99/4‘, ‘2998+10‘, ‘568/14))-(-4‘, ‘3)/(16-3‘, ‘2) )‘]

content = "‘1 - 2 * ((60-30+1*(9-2*5/3+7/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2) )‘"
new_content = re.split(‘[\\+\\-\\*\\/]+‘, content)
# new_content = re.split(‘\\*‘, content, 1)
print(new_content)
#["‘1 ", ‘ 2 ‘, ‘ ((60‘, ‘30‘, ‘1‘, ‘(9‘, ‘2‘, ‘5‘, ‘3‘, ‘7‘, ‘3‘, ‘99‘, ‘4‘, ‘2998‘, ‘10‘, ‘568‘, ‘14))‘,
#  ‘(‘, ‘4‘, ‘3)‘, ‘(16‘, ‘3‘, "2) )‘"]

inpp = ‘1-2*((60-30 +(-40-5)*(9-2*5/3 + 7 /3*99/4*2998 +10 * 568/14 )) - (-4*3)/ (16-3*2))‘
inpp = re.sub(‘\\s*‘,‘‘,inpp)                #把空白字符去掉
print(inpp)
new_content = re.split(‘\\(([\\+\\-\\*\\/]?\\d+[\\+\\-\\*\\/]?\\d+){1}\\)‘, inpp, 1)
print(new_content)
#[‘1-2*((60-30+‘, ‘-40-5‘, ‘*(9-2*5/3+7/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2))‘]

补充r‘ ‘ 转义

技术分享
fdfdsfds\\fds
sfdsfds& @$
lzl.txt

首先要清楚,程序读取文件里的\\字符时,添加到列表里面的是\\\\

import re,sys
li = []
with open(‘lzl.txt‘,‘r‘,encoding="utf-8") as file:
    for line in file:
        li.append(line)
print(li)                   # 注意:文件中的单斜杠,读出来后会变成双斜杠
# [‘fdfdsfds\\\\fds\\n‘, ‘sfdsfds& @$‘]
print(li[0])                # print打印的时候还是单斜杠
# fdfdsfds\\fds

r字符的意义,对字符\\进行转义\\只做为字符出现:

import re,sys
li = []
with open(‘lzl.txt‘,‘r‘,encoding="utf-8") as file:
    for line in file:
        print(re.findall(r‘s\\\\f‘, line))  #第一种方式匹配
        # print(re.findall(‘\\\\\\\\‘, line))  #第二种方式匹配
        li.append(line)
print(li)                   # 注意:文件中的单斜杠,读出来后会变成双斜杠
# [‘s\\\\f‘]
# []
# [‘fdfdsfds\\\\fds\\n‘, ‘sfdsfds& @$‘]

补充:看完下面的代码你可能更懵了

import re
re.findall(r‘\\\\‘, line)  # 正则中只能这样写 不能写成 r‘\\‘ 这样
print(r‘\\\\‘)            # 只能这样写 不能写成r‘\\‘ \\只能是双数
# \\\\        结果
# 如果想值打印单个\\ 写成如下
print(‘\\\\‘)             # 只能是双数
# \\         结果

总结:文件中的单斜杠\\,读出到程序中时是双斜杠\\\\,print打印出来是单斜杠\\;正则匹配文件但斜杠\\时,用r‘\\\\‘双斜杠去匹配,或者不用r直接用‘\\\\\\\\‘四个斜杠去匹配

、compile函数

说明:

Python通过re模块提供对正则表达式的支持。使用re的一般步骤是先使用re.compile()函数,将正则表达式的字符串形式编译为Pattern实例,
然后使用Pattern实例处理文本并获得匹配结果(一个Match实例),最后使用Match实例获得信息,进行其他的操作

举一个简单的例子,在寻找一个字符串中所有的英文字符:

import re
pattern = re.compile(‘[a-zA-Z]‘)
result = pattern.findall(‘as3SiOPdj#@23awe‘)
print(result)
# [‘a‘, ‘s‘, ‘S‘, ‘i‘, ‘O‘, ‘P‘, ‘d‘, ‘j‘, ‘a‘, ‘w‘, ‘e‘]

匹配IP地址(255.255.255.255):  

import re

pattern = re.compile(r‘^(([1-9]?\\d|1\\d\\d|2[0-4]\\d|25[0-5])\\.){3}([1-9]?\\d|1\\d\\d|2[0-4]\\d|25[0-5])$‘)
result = pattern.match(‘255.255.255.255‘)
print(result)
# <_sre.SRE_Match object; span=(0, 15), match=‘255.255.255.255‘>

 

  

12、urllib模块

在能使用的各种网络函数库中,功能最强大的可能是urllib和urllib2(python2.0)了。通过他们在网络上访问文件,就好像访问本地电脑的文件一样,通过一个简单的函数调用,几乎可以把任何URL执行的东西用做程序的输入,想象一下这个模块和re模块集合:可以下载web页面,提前信息,以及自动生成报告等。

#!/usr/bin/env python
# -*- coding:utf-8 -*-
#-Author-Lian

import urllib.request

def getdata():
    url = "http://www.baidu.com"
    data = urllib.request.urlopen(url).read()
    data = data.decode("utf-8")
    print(data)

getdata()

urlopen返回的类文件对象支持close、read、readline、和readlines方法

 

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