CODEWITHSUNDEEP
pythonarraysnumpyreshape
sdsnaught
sdsnaught

Reputation: 9

How to split/reshape a numpy array

I have a numpy array called 'results' which is defined like this

array([1, 2, 3, 4, 5, 6])

but I need it to look like this:

array([1, 2], [3, 4], [5, 6])

How can I convert 'results' into this new array in Python? The array I end up with still needs to be a numpy array.

Upvotes: 1

Views: 2098

Answers (1)

sapi
sapi

Reputation: 10224

You can achieve this directly by using the reshape method.

For example:

In [1]: import numpy as np

In [2]: arr = np.array([1, 2, 3, 4, 5, 6])

In [3]: reshaped = arr.reshape((3, 2))

In [4]: reshaped
Out[4]: 
array([[1, 2],
       [3, 4],
       [5, 6]])

Note that where possible, reshape will give you a view of the array. In other words, you're looking at the same underlying data as for the original array:

In [5]: reshaped[0][0] = 7

In [6]: reshaped
Out[6]: 
array([[7, 2],
       [3, 4],
       [5, 6]])

In [7]: arr
Out[7]: array([7, 2, 3, 4, 5, 6])

This is almost always an advantage. However, if you don't want this behaviour, you can always take a copy:

In [8]: copy = np.copy(reshaped)

In [9]: copy[0][0] = 9

In [10]: copy
Out[10]: 
array([[9, 2],
       [3, 4],
       [5, 6]])

In [11]: reshaped
Out[11]: 
array([[7, 2],
       [3, 4],
       [5, 6]])

Upvotes: 5

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