从变量中进行 Numpy 切片 [英] Numpy slicing from variable

问题描述

我正在尝试使用在变量中预定义的切片对 numpy 数组进行切片.这有效:

I'm trying to slice a numpy array using a slice that is predefined in a variable. This works:

b = fromfunction(lambda x,y: 10*x+y, (5,4),dtype=int) # Just some matrix

b[1:3,1:3]
# Output:
# array([[11, 12],
#       [21, 22]])

但我想做的是这样的事情:

But what I want to do is somthing like this:

slice = "1:3,1:3"
b[slice]
# Output:
# array([[11, 12],
#       [21, 22]])

切片变量的类型对我来说并不重要，我只是以字符串为例.如何保存这样的切片说明符?

It is not important to me what type the slice-variable has, I'm just using a string as an example. How do I save a slice-specifier like that?

推荐答案

可以使用内置的slice函数

s = slice(1,3)
b[s,s]

ds = (s,s)
b[ds]

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