python 函数 概括

函数

作用
避免重复代码
方便修改 扩展性高
保持代码一致性

def doso():
    print('222')

if 1:
    doso()
else:
    doso()

def add(x,y):
    print(x,y)

print(add([3,2],3))

import time

def logger(n):
    time_format = '%Y-%m-%d $X'
    time_current = time.strftime(time_format)
    with open('日志记录','a') as f:
        f.write('%s end action%s\n' %(time_current,n))
def action1(n):
    print('starting action1...')
    logger(n)

def action2(n):
    print('starting action2...')

action1(2222)

函数的参数  默认参数一定跟在后面
def inf(name, age, sex='male'):
    print('name %s' % name)
    print('sex %s' % sex)
    print('age %d' % age)

inf('xiao', 12)
inf('big', 25, 'female')
inf(age=29, name='sss')

不定长参数

def add(x, y):
    print(x + y)

add(1,2)

def add(*args):
    s = 0
    for i in args:
        s+=i
    return s

print(add(1,2,3,1))


def print_info(*args, **kwargs):
    print(args)
    print(kwargs)


print_info('alex', 18, 'male', job='it', hobby='girls')

报错 顺序不能颠倒 print_info('alex', 'male', job='it', 18, hobby='girls')

函数的return    功能：结束函数  返回指定对象

返回什么内容  给谁
def f():
    print('ok')
    return 'ok'


f()
注意点
1 函数里如果没有return  会默认返回None
2 如果 return 多个对象，那么py会帮我们把这多个对象封装成一个元祖返回

函数作用域
if True:
    x = 3
print(x)

x = int(2.9)


g_count = 0  #global


def outer():
    enclosing
    o_count = 1

    def inner():
        i_count = 2 # local
        print(o_count)


    print(i_count)  # 找不到

    inner()

outer()


count = 10

def outer():
    print(count)
    count = 100
    print(count)

outer()