函数与几项简单的模块

Posted 2021-06-11 wuc123

检测指针当前位置

with open(\'a.txt\',\'wt\',encoding=\'utf-8\') as f:
    print(f.tell)     # 检测指针当前位置所在

编写日志功能

import time    # 使用 时间模块包
with open(\'日志的位置\',mode=\'at\',encoding=\'utf-8\') as f:
    f.write(\'%s ...内容\\n\' % time.strftime(\'%Y-%m-%d %H:%M:%S\'))  后面时间格式
    
# 监控日志
with open(\'日志位置\',mode=\'rb\') as f:
    f.seek(0,2)               # 指针移动到末尾
    while True:
        line = f.realine()
        if len(line) == 0:
            continue
        else:
            print(line.decode(\'utf-8\'), end=\'\' )

修改文件的两种方式

1.
with open(\'a.txt\',mode=\'rt\',encoding=\'utf-8\') as f:
    res = f.read()
with open(\'a.txt\',mode=\'wt\',encoding=\'utf-8\') as f:
    f.write(res.replace(\'需要替换的内容...\'，\'替换成什么内容...\'))

2.
import os

with open(\'a.txt\',mode=\'rt\',encoding=\'utf-8\') as f,\\
        open(\'临时文件名...\'，\'wt\',encoding=\'utf-8\') as f1:
    for line in f:
        f1.write(line.replace(\'需要替换的内容...\',\'替换成什么内容...\'))
os.remove(\'a.txt\')
os.rename(\'临时文件名...\',\'a.txt\')

函数

1.定义函数与调用函数

def func():             # func = 函数的内存地址
    print(\'....\')    

func()

2.函数定义阶段发生的事情

申请内存空间，把函数体代码放进去，然后把内存地址绑定给函数名

def func():
    print(1)
    print(2)
    

3.函数调用阶段发生的事情：执行函数体代码

def func():
    print(1)
    print(2)
    saadad
    
func()    
# 函数定义阶段只检测语法不执行代码，只有在调用函数时才会执行函数体代码

例1
def bar():
    print(\'from bar\')

def foo():
    print(\'from foo\')
    bar()
                                 #   from foo    
foo()                            #    from bar

例2
def foo():
    print(\'from foo\')
    bar()
    
def bar():
    print(\'from bar\')
                                           #   from foo    
foo()                                       #    from bar

4.函数的参数

例
def add(x,y):
    res = x + y
    print(res)
    
add(2,3)


def func(x,y):
    if x > y:
        print(x)
    else:
        print(y)

func(3333,4444)


def log(user,pwd):
    if user == \'wuc\' and pwd == \'123\'
        print(\'ok\')
    else:
        print(\'error\')
        
log(\'wuc\',\'123\')        

5.函数的返回值 return

函数内可以有多个return,但只要执行一次,整个函数就立即结束,并且将return后的值当作本次调用的产品返回

def max(sal1,sal2):
    if sal1 > sal2:
        return sal1
    else:
        return sal2
res = max(1000,2000)
print(res * 12)

#具体来说函数的返回值有三种形式
# 1 return 值: 返回的就是该值本身/-
# 2 return 值1,值2,值3:返回的是小元组

def func():
    return 111,\'aaa\',[11,22]

x,y,z = func()
print(x,y,z)

# 没有return或者return无值或者return None:返回的都是None

del func():
    res = 1+2
    return

res = func()
print(res)                 #  None

模块

"""
1 什么是模块
    模块一系列功能的集合体

    模块分为四种通用的类别
    　　1 使用python编写的.py文件

    　　2 已被编译为共享库或DLL的C或C++扩展

    　　3 把一系列模块组织到一起的文件夹（注：文件夹下有一个__init__.py文件，该文件夹称之为包）

    　　4 使用C编写并链接到python解释器的内置模块

    模块有三种来源:
        1 python自带的模块/库
            内置模块
            标准库

        2 第三方的库

        3 自定义库

2 为何要用模块
    1 拿来主义,提升开发效率
    2 减少代码冗余

3 如何用模块
    import
    from ... import
"""

例
import spam
print(spam.x)
print(spam.f1)
print(spam.f2)

def f1():
    print(\'xxxxx\')
    
spam.f1()
spam.f2()



from spam import x ,f1,f2

def f1():
    print(\'xxxxx\')

f1()

常用模块

时间戳

1. import time  
print(time.time())   1970到现在的秒数

2.格式化字符
print(time.strftime(\'%Y-%m-%d %H:%M:%S\'))

3.结构化时间
obj = time.localtime()
print(obj.tm_year)
print(obj.tm_yday)
print(obj)

obj2 = time.gmtime()   # utc时间
print(obj2)

random模块

# print(random.random())
# print(random.randint(1,3))
# print(random.randrange(1,3))
# print(random.choice([11,"aaa",333]))
# print(random.sample([11,"aaa",333,444],2))

# print(random.uniform(1, 3))

# item=[1,3,5,7,9]
# random.shuffle(item)
# print(item)

# 储备知识
# print(chr(65))
# print(chr(90))
#
# print(ord(\'A\'))
# print(ord(\'Z\'))


import random
                                       # 随机验证码的命令
def make_code(size):
    res = \'\'
    for i in range(size):
        num = str(random.randint(0,9))
        s = chr(random.randint(65,90))
        res += random.choice([num,s])
    return res


print(make_code(6))

os 模块

import os

# print(os.getcwd())  # pwd

# os.makedirs(\'a/b/c/d\')
# os.rmdir(\'a/b/c/d\')
# os.removedirs(\'a/b/c/d\')
# l = os.listdir(r\'D:\\py18期\\day11\')
# print(l)

# print(os.listdir(\'.\'))
# print(os.listdir(\'..\'))
# print(os.listdir(\'../..\'))

# print(os.listdir(\'.\'))
# print(os.listdir(\'..\'))
# print(os.listdir(\'../..\'))

# obj=os.stat(\'a.txt\')  # stat a.txt
# print(obj.st_size)
# print(os.sep)
# print(os.linesep)

# print(os.name)

# print(os.environ)

# os.environ[\'username\'] = "egon"
#
# print(os.environ)

# print(os.path.abspath(r"a\\b\\c"))

# print(__file__)

# print(os.path.split(r"D:\\a\\b\\c\\d.txt"))
# print(os.path.dirname(os.path.dirname(r"D:\\a\\b\\c\\d.txt")))
# print(os.path.basename(r"D:\\a\\b\\c\\d.txt"))

# print(os.path.exists(r"D:\\py18期\\day11\\代码\\a"))
# print(os.path.exists(r"D:\\py18期\\day11\\代码\\a.txt"))
# print(os.path.isfile(r"D:\\py18期\\day11\\代码\\a"))
# print(os.path.isfile(r"D:\\py18期\\day11\\代码\\a.txt"))
# print(os.path.isdir(r"D:\\py18期\\day11\\代码\\a"))
# print(os.path.isdir(r"D:\\py18期\\day11\\代码\\a.txt"))

# print(os.path.isabs(r\'D:\\py18期\\day11\\代码\\a\'))

# print(os.path.getsize(\'a.txt\'))
# print(os.path.join(\'D:\\\\\', "a", \'b\', \'c.txt\'))
# print(os.path.join(\'D:\\\\\', "a", "C:\\\\" \'b\', \'c.txt\'))


# print(os.path.dirname(os.path.dirname(__file__)))

# res = os.path.normpath(os.path.join(__file__,"..",\'..\'))
# print(res)

subprocess 模块

import os

# tasklist | findstr python.exe
# taskkill /F /PID 30060
# os.system(\'tasklist | findstr chrome\')
# res = os.system(\'tasklist\')
# print(\'=\'*50)
# print(res)

import subprocess
import time

obj = subprocess.Popen(\'tasklist\',shell=True,
                 stdout=subprocess.PIPE,
                 stderr=subprocess.PIPE
                 )
# print(\'hello\')
# time.sleep(3)

res1 = obj.stdout.read()
res2 = obj.stderr.read()
print(res1.decode(\'gbk\'))
print(res2)