python变量作用域

制作人：全心全意

python中全局变量和局部变量可以同名，但互不干扰

a = 10
def myfun():
    a = 20
    print(a)
myfun()    #20
print(a)    #10

global和nonlocal的使用

a = 10
def myfun():
    a = 20
    def mynest():
        global a  
        a = 30
        print(a)    #30
    mynest()
    print(a)    #20
myfun()
print(a)    #30

a = 10
def myfun():
    a = 20
    def mynest():
        nonlocal a
        a = 30
        print(a)    #30
    mynest()
    print(a)    #30
myfun()
print(a)    #10