Python 3：有些反转if语句(Python 3: some reversed if statement)

Python 3：有些反转if语句(Python 3: some reversed if statement)

在我的教科书中，我遇到了这个例子：

lower = (lambda x, y: x if x < y else y) print(lower ('bb','aa'))

到目前为止我用过

if_stmt ::= "if" expression ":" suite ( "elif" expression ":" suite )* ["else" ":" suite]

所以，这个'x if x <y else y'让我有点惊讶。 你可以指导我：在文档中哪里可以找到这种结构？

先谢谢你

In my textbook I came across this example:

lower = (lambda x, y: x if x < y else y) print(lower ('bb','aa'))

So far I used

if_stmt ::= "if" expression ":" suite ( "elif" expression ":" suite )* ["else" ":" suite]

So, this 'x if x < y else y' astonished me a bit. Could you direct me: where in the documentation can I find this construction?

Thank you in advance

最满意答案

所以它们被称为“条件表达式”，您可以在python 3文档中找到它们，可以在2.5文档的这一部分中找到更清晰的解释。 我对条件赋值使用了很多，比如：

level = 1 if logging else 0

So they are called "Conditional Expressions" and you can find them in the python 3 docs a longer clearer explanation can be found in this section of of the 2.5 docs. I use it a lot for conditional assignment like:

level = 1 if logging else 0