Python交换两个变量值的函数

方法1：(错误)

def func(a,b):
    a,b = b,a

a = 1
b = 2
func(a,b)
print(a,"   ",b)

方法2：（正确）

def func(a,b):
    return b,a

a = 1
b = 2
a,b = func(a,b)
print(a,"   ",b)