Python中的多个“或"条件

问题描述

我有一点代码问题,它适用于 IDLE 而不是 Eclipse,我可以这样写吗:

I have a little code issue and it works with IDLE and not with Eclipse, can I write this :

if  fields[9] != ('A' or 'D' or 'E' or 'N' or 'R'):

而不是这个:

if  fields[9] != 'A' and fields[9] != 'D' and fields[9] != 'E' and fields[9] != 'N' and fields[9] != 'R':

谢谢.


解决方案

使用 not in 和一个序列:

if fields[9] not in ('A', 'D', 'E', 'N', 'R'):

它针对一个元组进行测试,Python 将方便有效地将其存储为一个常量.您还可以使用集合文字:

which tests against a tuple, which Python will conveniently and efficiently store as one constant. You could also use a set literal:

if fields[9] not in {'A', 'D', 'E', 'N', 'R'}:

但仅限于更新版本的 Python(Python 3.2 和更新版本) 会将其识别为不可变常量.对于较新的代码,这是最快的选择.

but only more recent versions of Python (Python 3.2 and newer) will recognise this as an immutable constant. This is the fastest option for newer code.

因为这是一个字符,你甚至可以使用一个字符串:

Because this is one character, you could even use a string:

if fields[9] not in 'ADENR':

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