为什么我应该使用operator.itemgetter(x)而不是[x]? [英] Why should I use operator.itemgetter(x) instead of [x]?

问题描述

这里有一个更普遍的问题:

There is a more general question here: In what situation should the built-in operator module be used in python?

最高答案声称operator.itemgetter(x)比"c2>"更整洁".我觉得事实恰恰相反.

The top answer claims that operator.itemgetter(x) is "neater" than, presumably, than lambda a: a[x]. I feel the opposite is true.

还有其他好处，例如性能吗?

Are there any other benefits, like performance?

推荐答案

除非您的代码处于紧密的内部循环中，并且实际上是性能问题，否则您不必担心性能.而是使用最能表达您意图的代码.有些人喜欢lambda，有些人喜欢itemgetter.有时候，这只是一个品味问题.

You shouldn't worry about performance unless your code is in a tight inner loop, and is actually a performance problem. Instead, use code that best expresses your intent. Some people like lambdas, some like itemgetter. Sometimes it's just a matter of taste.

itemgetter功能更强大，例如，如果您需要一次获取多个元素.例如:

itemgetter is more powerful, for example, if you need to get a number of elements at once. For example:

operator.itemgetter(1,3,5)

与以下相同:

lambda s: (s[1], s[3], s[5])

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