How do I extract a sub-array from a numpy 2d array? [duplicate]

Question

I'd like to extract a numpy array with a specified size from a numpy 2d array--essentially I want to crop the array. For example, if have a numpy array like this:

([1,2,3],
 [4,5,6],
 [7,8,9])

I'd like to extract a 2x2 from it and the result should be:

([1,2],
 [4,5])

How can I do that?

You can use numpy indexing array[:2,:2]

Kasravnd
– Kasravnd

2016-02-28 10:00:27 +00:00
Commented Feb 28, 2016 at 10:00 — Kasravnd
– Kasravnd, Commented Feb 28, 2016 at 10:00

Mike Müller · Accepted Answer · 2016-02-28 09:59:50Z

57

Given this array:

>>> a
array([[1, 2, 3],
       [4, 5, 6],
       [7, 8, 9]])

You can slice it along both dimensions:

>>> a[:2,:2]
array([[1, 2],
       [4, 5]])

answered Feb 28, 2016 at 9:59

Mike Müller

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