# 全局变量    如果函数的内容无 global关键字，优先读取全局变量，无法对全局变量重新赋值，

name = 'mj'

def change_name():

    print('change_name',name)

change_name()

change_name mj

# 但是对于可变类型，可以对内部进行操作。

name = ['mj','hm']

def change_name():

    name.append('xiaoma')

    print('change_name',name)

change_name()

print(name)

change_name ['mj', 'hm', 'xiaoma']

['mj', 'hm', 'xiaoma']

#如果函数中有global关键字，变量本质上就是全局变量的那个变量，可读取可赋值

name = 'mj'

def change_name():

    global name

    print('change_name',name)

change_name()

print(name)

change_name mj

mj

# 局部变量

name = 'mj'

def change_name():

    name = 'love'

    print('change_name',name)

change_name()

print(name)

change_name love

mj

# 修改全局变量  global

name = 'mj'

def change_name():

    global name

    name = 'love'

    print('change_name',name)

change_name()

print(name)

change_name love

love

NAME = ['mj','hm']

def change_name():

    name = 'love'

    print('change_name',name)

change_name()

print(NAME)

change_name love

['mj', 'hm']

# 指定上一级变量  nonlocal

name = '中国'

def city():

    name = '上海'

    def shiji():

        nonlocal name

        name = '九亭'

    shiji()

    print(name)

print(name)

city()

print(name)

中国

九亭

中国