Question

我有一个numpy数组arr = np.arange(20).reshape(2,10)。我想定义切片sli = slice(start,stop, step)，然后再访问arr[0,sli]。如何定义sli以使arr[0,sli]成为整个数组？即sli=:

我已经尝试过了：

sli = slice(0,-1) # equivalent to arr[0,:-1]
sli = slice(0,0) # equivalent to []
sli = slice(0) # equivalent to []
sli = slice(0,10) # works fine, but i might not know the shape of arr
                  # at the time I define sli

Answer 1

使用Ellipsis表示法：

import numpy as np

arr = np.arange(20).reshape(2,10)
sli = ...
out = arr[0, sli]

print(out)    
array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])

适用于python3.x。对于旧版本，您应该使用slice(None)。

Answer 2

评论JonClements

http://example.com/my_app/class/3/

使用切片函数返回整个数组

2 个答案: