在Python中切片列表列表 [英] slicing list of lists in Python

问题描述

我需要在python中切片列表列表.

I need to slice a list of lists in python.

A = [[1,2,3,4,5],[1,2,3,4,5],[1,2,3,4,5]]
idx = slice(0,4)
B = A[:][idx]

上面的代码没有给我正确的输出.

The code above isn't giving me the right output.

我想要的是:[[1,2,3],[1,2,3],[1,2,3]]

推荐答案

使用numpy十分简单-您可以执行切片:

With numpy it is very simple - you could just perform the slice:

In [1]: import numpy as np

In [2]: A = np.array([[1,2,3,4,5],[1,2,3,4,5],[1,2,3,4,5]])

In [3]: A[:,:3]
Out[3]: 
array([[1, 2, 3],
       [1, 2, 3],
       [1, 2, 3]])

您当然可以将numpy.array转换回list:

In [4]: A[:,:3].tolist()
Out[4]: [[1, 2, 3], [1, 2, 3], [1, 2, 3]]

这篇关于在Python中切片列表列表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！