如果它的索引在另一个列表上，则从列表中获取项目

Question

嗯，我在网站上看，我没有找到任何可以帮助我的东西，所以我来问了。 如果它的索引在另一个列表中，我如何从列表中获取项目？

例子：

我有一组向量：

[[0.0,0.0,0.1] [0.4,0.23,0.175] [0.0,1.,0.5] [0.0,0.03,0.1] [0.02,0.0,0.3]]

和索引列表：

[0,2,3]

我想要这样的结果：

[[0.0,0.0,0.1] [0.0,1.,0.5] [0.0,0.03,0.1]]

我怎样才能得到这个结果？ 感谢任何帮助:)

Answer 1

像这样的东西

lst1 = [[0.0, 0.0, 0.1], [0.4, 0.23, 0.175], [0.0, 1., 0.5], [0.0, 0.03, 0.1], [0.02, 0.0, 0.3]]
lst2 = [0, 2, 3]
lst3 = [x for idx, x in enumerate(lst1) if idx in lst2]
print(lst3)

输出

[[0.0, 0.0, 0.1], [0.0, 1.0, 0.5], [0.0, 0.03, 0.1]]

Answer 2

你可以通过列表理解来做到这一点。

例如：

mylist = [[0.0,0.0,0.1], [0.4,0.23,0.175], [0.0,1.,0.5], [0.0,0.03,0.1], [0.02,0.0,0.3]]
indices = [0,2,3]
result = [mylist[i] for i in indices]

结果现在是[[0.0, 0.0, 0.1], [0.0, 1.0, 0.5], [0.0, 0.03, 0.1]]