本文介绍了Python：if / else in dict的理解？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
在python2.7 +存在任何方式来做如下：
In python2.7+ exist any way to make something like:
{ something_if_true if condition else something_if_false for key, value in dict_.items() }
我知道你可以做任何事情只是'if'
I know you can make anything with just 'if'
{ something_if_true for key, value in dict_.items() if condition}
推荐答案
你已经得到它： A如果测试其他B 是一个有效的python表达式。你的dict理解的唯一问题是，在一个字母理解中表达的地方必须有两个表达式，用冒号分隔：
You've already got it: A if test else B is a valid python expression. The only problem with your dict comprehension as shown is that the place for an expression in a dict comprehension must have two expressions, separated by a colon:
{ (some_key if condition else default_key):(something_if_true if condition
else something_if_false) for key, value in dict_.items() }
最终 if 子句作为过滤器，与具有条件表达式不同
The final if clause acts as a filter, which is different from having the conditional expression.
这篇关于Python：if / else in dict的理解？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！