Python 基础 - Day 5 Learning Note - 模块 之 介绍篇

Posted 2020-10-03

定义

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模块（module）支持从逻辑上组织Python代码，本质就是.py结尾的python文件（e.g.文件名：test.py; 模块名：test），目的是实现某项功能。将其他模块属性附加到你的模块中的操作叫导入（import）。

模块分为三类：标准库、开源模块（open source module)和自定义模块。

包（package）是一个有层次的文件目录结构， 定义了一个由模块和子包组成的python应用程序执行环境。和模块及类一样，也使用句点属性标识来访问他们的元素。使用标准的import和from-import语句导入。

导入模块

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导入常用语法

模块导入本质就是一个路径搜索的过程。 即在文件系统“预定义区域”查找你所需要的模块文件。 预定义区域是python搜索路径的集合 - 列表。

# 方法一
import mudule_name  #导入整个模块，载入时执行

import module_name as MA   # 扩张 as 

# 方法二
from module_name import name1   # 导入指定模块属性

from module_name import name1 as n1 # 扩张 as  

#特别注意fe
from . import test1  # 相对导入，自当前目录导入test1

from module_name import*   # 不建议使用，非良好编程风格，很可能覆盖当前名称空间中现有的名字。

#!usr/bin/envpython
#-*-coding:utf-8-*-

importsys,os

print(sys.path)#返回为列表，包含模块库的路径

x=os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
sys.path.append(x)#将指定含有自定义的模块存入模块库路径列表中

将自定义模块添加到路径搜索区域中

import语句和from-import语句的区别

在import语句下，调用模块属性 需要 使用属性/句点属性标识 （如 module_name.logger() 或 os.path.abspath()）的方式。 import语句的本质是将 模块中所有的代码 赋值给 模块名。

而from-import语句是 copy了模块中指定属性的代码并在当前文件下执行。所以，在from-import语句下，不需要用句点属性标识，直接可以调用函数或者类 （logger()）。 在效率上，由于运行方式的不同， from-import语句比import语句的速度更快。

标准库的分类

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标准库就其大致用途可分为四类：data persistence and exchange, in-memory data structure, file access, and text process tools。以下是python module of the week 的详细分类

Categories	Module name	Brief
Built-in objects	exceptions	built-in error classes （自动导入）
String service	codes	string encoding and decoding
	difflib	working with text
	String IO and cStringIO	work with text buffers using file-like API (read, write. etc.)
	re	regular expression
	struct	working with Binary Data
	textwrap	formatting text paragraphs
Data type	array	sequence of fixed-type data
	datetime	date/time value manupulation
	calendar	work with dates
	collections	container data types
	heapq	in-place heap sort algorithm
	bisect	maintain lists in sorted order
	sched	generic event scheduler
	Queue	a thread-safe FIFO implementation (comparied with built-in function such as pop() and insert())
	weakref	garbage-collectable references to objects
	copy	duplicate objects
	pprint	pretty-print data structure
Numeric & mathematical module	decimal	fixed and floating point math
	fractions	rational numbers
	functools	toos for manipultaing functions
	itertools	iterator functions for efficient looping
	math	mathematical function
	operator	functional interface to built-in operators
	random	pseudorandom number generator
Internet data handling	base64	encode binary data into ASCII characters
	json	JavaScript Object Notation Serializer
	mailbox	access and manipulate emial achives
	mhlib	work with MH mailboxes
File formats	cvs	comma-separated value files
	ConfigParser	work with configuration files
	robotparser	internet spider access control
Cryptographic services	hashlib	cryptographic hashes and messary digests
	hmac	cryptographic signature and verification of messages
File and Directory access	os.path	platform-independent manipulation of file names
	fileinput	process lines from input streams
	filecmp	compare files
	tempfile	create temporary filesystem resources
	glob	filename pattern matching
	fnmatch	compare filenames against Unix-style glob partterns
	linecache	read text files efficiently
	shutil	high-level file opeerations
	dircache	cache directory listings
Data compression and archiving	bz2	bzip2 compression
	gzip	read and write GNU zip files
	tarfile	tar archive access
	zipfile	read and write ZIP archive files
	zlib	low-level access to GNUzlib compression library
Data persistence	anydbm	access to DBM-style database
	dbhash	DBM-style API for the BSD database library
	dbm	simple database interface
	dumbdbm	portable DBM implementation
	gdbm	GNU‘s version of the dbm library
	pickle and cPickle	python object serialization
	shelve	persistent storage of arbitrary Python objects
	whichdb	identify DBM-style database formats
	sqlite3	embedded relational database
Generic operating system service	os	portable access to operating system specific features
	time	functions for manipulating clock time
	getopt	command line option parsing
	optparse	command line option parser to replace getopt
	argparse	command line option and argument parsing
	logging	report status, error, and informational messages
	getpass	prompt the user for a password without echoing
	platform	access system version information
Optional operating system services	threading	manage concurrent threads
	mmap	memory-map files
	multiprocessing	manage processes like threads
	readline	interface to the GNU readline library
	rlcompleter	adds tab-completion to the interactive interpreter
Unix-specific services	commands	run external shell commands
	grp	Unix group database
	pipes	Unix shell command pipeline templates
	pwd	Unix password database
	resource	system resource management
Interprocess communication and networking	asynchat	asynchronous protocol handler
	asyncore	asynchronous I/O handler
	signal	receive notification of asynchronous system events
	subprocess	work with additional processes
Internet protocols and support 网络协议及支持	BaseHTTPServer	base classes for implementing web servers
	cgitb	detailed traceback reports
	Cookies	HTTP Cookies
	imaplib	IMAP4 client library
	SimpleXMLRPCServer	implemens an XML-RPC server
	smtpd	Sample SMTP Servers
	smtplib	Simple Mail Transfer Protocol client
	socket	Network Communication
	select	wait for I/O Efficiently
	SocketServer	Creating network servers
	urllib	simple interface for network reserouce access
	urllib2	Library for opening URLs
	urlparse	split URL into component pieces
	uuid	universally unique identifiers
	webbrowser	Displays web pages
	xmlrpclib	client-side liabrary for XML-RPC communication
Structured markup processing tools	xml.etree.ElementTree	XML manipulation API
Internationalization 国际化	gettext	Message Catalogs
	locale	POSIX cultural localization API
Program frameworks 程序框架	cmd	create line-oriented command processes
	shlex	lexical analysis of shell-style syntaxes
Development Tools 开发工具	doctest	Testing through documentation
	pydoc	Online help for python modules
	unittest	Automated testing framework
	pdb	Interative Debugger
Debugging and Profiling	profile, cProfile, and pstats	Performance analysis of Python programs
	timeit	Time the execution of samll bits of Python code
	trace	Follow Python statements as they are executed
Python Runtime Services	abc	Abstract Base Classes
	atexit	Call functions when a program is closing down
	contextlib	context manager utilities
	gc	Garbage Collector
	inspect	Inspect live objects
	site	Site-wide configuration
	sys	System-specific Configuration
	sysconfig	Interpreter Compile-time Configuration
	traceback	Extract, format, and print exceptions and stack traces
	warnings	Non-fatal alerts
Python Language Services	compileall	Byte-compile Source Files
	dis	Python Bytecode Disassembler
	pyclbr	Python class browser support
	tabnanny	Indentation validator
Importing Modules	imp	Interfact to module import mechanism
	pkclbr	Package Utilities
	zipimport	Load Python code from inside ZIP archives
Miscelaneous	EasyDialogs	Carbon dialogs for Mac OS X
	plistlib	Manipulate OS X property list files

 Source: python module of the week,  Douh Hellmann

 

Reference

http://www.cnblogs.com/wupeiqi/articles/4963027.html

http://www.cnblogs.com/alex3714/articles/5161349.html

module of the week, 全部标准库模块的释义，非常有用。