为什么我的函数输出打印出“无"?

问题描述

I just learned (am learning) how function parameters work in Python, and I started experimenting with it for no apparent reason, when this:

def jiskya(x, y):
    if x > y:
        print(y) 
    else:
        print(x) 

print(jiskya(2, 3))

gave the ouput:

>>>
2
None

Where did the None come from? And what is it?

解决方案

It's the return value of the function, which you print out. If there is no return statement (or just a return without an argument), an implicit return None is added to the end of a function.

You probably want to return the values in the function instead of printing them:

def jiskya(x, y):
    if x > y:
        return y
    else:
        return x

print(jiskya(2, 3))