知道其索引的多个列表元素 [英] Access multiple elements of list knowing their index

问题描述

我需要从给定列表中选择一些元素，知道它们的索引。假设我想创建一个新列表，其中包含索引为1,2,5的元素，来自给定列表[-2,1,5,3,8,5,6]。我做的是：

I need to choose some elements from the given list, knowing their index. Let say I would like to create a new list, which contains element with index 1, 2, 5, from given list [-2, 1, 5, 3, 8, 5, 6]. What I did is:

a = [-2,1,5,3,8,5,6]
b = [1,2,5]
c = [ a[i] for i in b]

有没有更好的方法呢？比如c = a [b]？

Is there any better way to do it? something like c = a[b] ?

推荐答案

你可以使用 operator.itemgetter ：

You can use operator.itemgetter:

from operator import itemgetter 
a = [-2, 1, 5, 3, 8, 5, 6]
b = [1, 2, 5]
print itemgetter(*b)(a)
# Result:
(1, 5, 5)

或者您可以使用 numpy ：

import numpy as np
a = np.array([-2, 1, 5, 3, 8, 5, 6])
b = [1, 2, 5]
print list(a[b])
# Result:
[1, 5, 5]

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但实际上，您目前的解决方案还不错。它可能是所有这些中最好的。

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But really, your current solution is fine. It's probably the neatest out of all of them.

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