Question

我的代码如下：

def hello(msg):
    return print(msg)


def hi(msg):
    t = 'this is a test time'
    return print(t + msg)


data = {0: hello, 1: hi}
for i in range(2):
    x = data.get(i)
    print(x('hello world '+str(i)))

然而输出是：

hello world 0
None
this is a test timehello world 1
None

问题是为什么我有两个None？

Answer 1

您得到None因为print语句没有返回值，它会向控制台输出一个值。

>>> a = print("Hi")
Hi
>>> print(a)
None

如果您想要将字符串添加到一起：

def hello(msg):
    return msg

def hi(msg):
    t = 'this is a test time'
    return t + msg

data = [hello, hi]
for i, func in enumerate(data):
    print(func('hello world ' + str(i)))

如果您想随机化函数的输出，请查看random.choice函数。

为什么我的函数中没有

1 个答案: