Python全局变量global

一个普通的例子

def func(x):
    print('this is x:', x)
    x = 2
    print('this is new x:', x)

x = 50
func(x)
print('this is also x:', x)

>>>this is x: 50
>>>this is new x: 2
>>>this is also x: 50

第二个例子

def func():

    global x 

    print('this is x:', x)

    x = 2

    print('this is new x:', x)

x = 50

func()

print('this is also x:' ,x)

>>>this is x: 50

>>>this is new x: 2

>>>this is also x: 2 

所以在前面定义好全局变量后，会一直反映在之后任意的地方