Talking about the function of Python

Advanced application file

r + to readable and writable, and is added in the back

w + function empty file is provided w

+ A A there is an additional function, a pointer is at the end of, a + a reading function is useless

Files modified in two ways

The first

with open('test', 'r', encoding='utf8') as fr, \
        open('test_swap', 'w', encoding='utf8') as fw:
    data = fr.read()
    data = data.replace('sb', 'dsb')

    fw.write(data)

import time
time.sleep(5)
os.remove('test.py')  # 删除文件
os.rename('test_swap.py', 'test.py')  # 重命名文件

The second

with open('test', 'r', encoding='utf8') as fr, \
        open('test_swap', 'w', encoding='utf8') as fw:
    for i in fr:
        i = i.replace('sb', 'dsb')
        fw.write(i)

os.remove('test.py')  # 删除文件
os.rename('test_swap.py', 'test.py')  # 重命名文件

Defined functions

Before the code block, and function names written on def

Function parameters

Parameter: the parameter definition phase only, in the form of parameters, use had nothing, accounts for only a position, with descriptive sense

Argument: only when invoked only argument is that the actual parameters, has a specific value

Location parameter: write a one parameter, called the location parameter

Location argument: a write past a position called the argument

Position and a position parameter argument is one to one from left to right

Default parameter: no transmission parameters, a default value may be used directly, used to pass parameters you pass values, the default parameter must be placed behind the position parameter

Keyword arguments: According to the parameter name can be given a specific value, you can break the rules must be one to one location parameter

Function's return value

return : you can return any data type, but it defaults is a tuple