从二维 numpy 数组中提取列

Question

I have 2d numpy array:

import numpy as np

a = np.array([[1,2,3,4],
              [4,5,6,7]])

How can I extract the following array?

result = array([[3,4],
               [6,7]]

Answer 1

That is called slicing , you can use <array>[<row indexes>,<column indexes>] .

Example -

import numpy as np

a = np.array([[1,2,3,4],
              [4,5,6,7]])

print(a[:,2:])
>>> [[3 4]
     [6 7]]