Python`如果x不是None`或`if not x is None`？

问题：

I've always thought of the if not x is None version to be more clear, but Google's style guide and PEP-8 both use if x is not None . 我一直认为if not x is None版本更清楚，但谷歌的风格指南和PEP-8都使用， if x is not None 。 Is there any minor performance difference (I'm assuming not), and is there any case where one really doesn't fit (making the other a clear winner for my convention)?* 是否存在任何轻微的性能差异（我假设没有），是否存在任何一个真正不合适的情况（使另一个成为我公约的明显赢家）？*

*I'm referring to any singleton, rather than just None . *我指的是任何单身人士，而不仅仅是None 。

...to compare singletons like None. ...比较像无的单身人士。 Use is or is not. 使用是否。

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解决方案：

参考一： https://stackoom.com/question/BNEq/Python-如果x不是None-或-if-not-x-is-None
参考二： https://oldbug.net/q/BNEq/Python-if-x-is-not-None-or-if-not-x-is-None

来源：oschina

链接：https://my.oschina.net/stackoom/blog/4351316