只需要索引:枚举还是(x)范围?

2022-01-24 00:00:00 python enumerate range

问题描述

如果我只想在循环中使用索引,我应该更好地使用 range/xrange 函数和 len()

If I want to use only the index within a loop, should I better use the range/xrange function in combination with len()

a = [1,2,3]
for i in xrange(len(a)):
    print i 

枚举?即使我根本不会使用 p ?

or enumerate? Even if I won't use p at all?

for i,p in enumerate(a):
    print i    


解决方案

我会使用 enumerate,因为它更通用 - 例如,它适用于可迭代对象和序列,以及仅返回引用的开销到一个对象并不是什么大不了的事 - 虽然 xrange(len(something)) 虽然(对我来说)更容易阅读你的意图 - 会破坏不支持 len 的对象...

I would use enumerate as it's more generic - eg it will work on iterables and sequences, and the overhead for just returning a reference to an object isn't that big a deal - while xrange(len(something)) although (to me) more easily readable as your intent - will break on objects with no support for len...

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