python中函式返回常用一下四種類型，

def test1():
    print("in the test1")#無返回值

def test2():
    print("in the test2")#返回0
    return 0
def test3():
    print("in the test3")#返回引數
    return 'test3'
def test4():
    print("in the test4")#返回函式
    return test2()
x=test1()
y=test2()
z=test3()
a=test4()
print(x)
print
 
(y)
print(z)
print(a)

對應執行結果如下：

in the test1
in the test2
in the test3
in the test4
in the test2
None
0
test3
0