列表理解:为什么这是语法错误? [英] List Comprehension: why is this a syntax error?

问题描述

为什么下面的列表理解中的print(x)在这里无效(SyntaxError)?

Why is print(x) here not valid (SyntaxError) in the following list-comprehension?

my_list=[1,2,3]
[print(my_item) for my_item in my_list]

与之相反，以下内容不会出现语法错误:

To contrast - the following doesn't give a syntax error:

def my_func(x):
    print(x)
[my_func(my_item) for my_item in my_list]

推荐答案

因为print不是函数，而是语句，所以不能在表达式中包含它们.如果您使用普通的Python 2语法，这将变得更加明显:

Because print is not a function, it's a statement, and you can't have them in expressions. This gets more obvious if you use normal Python 2 syntax:

my_list=[1,2,3]
[print my_item for my_item in my_list]

那看起来不太正确. :)围绕my_item的括号会欺骗您.

That doesn't look quite right. :) The parenthesizes around my_item tricks you.

这在Python 3 btw中有所改变，其中print 是一个函数，您的代码可以正常工作.

This has changed in Python 3, btw, where print is a function, where your code works just fine.

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