how to do circular shift in numpy

python arrays numpy shift
LWZ picture LWZ · Apr 3, 2013 · Viewed 35.3k times · Source

I have a numpy array, for example

a = np.arange(10)

how can I move the first n elements to the end of the array?

I found this roll function but it seems like it only does the opposite, which shifts the last n elements to the beginning.

Answer

mgilson picture mgilson · Apr 3, 2013

Why not just roll with a negative number?

>>> import numpy as np
>>> a = np.arange(10)
>>> np.roll(a,2)
array([8, 9, 0, 1, 2, 3, 4, 5, 6, 7])
>>> np.roll(a,-2)
array([2, 3, 4, 5, 6, 7, 8, 9, 0, 1])

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