wrapping around slices in Python / numpy

Question

I have a numpy array, and I want to get the \"neighbourhood\" of the i\'th point. Usually the arrays I\'m using are two-dimensional, but the following 1D example illustrates

Answer 1

I know this question is old, but should mention scipy.ndimage.filter.generic_filter.

It has a mode='wrap' option, plus it handles the application of the neighbor function.

import scipy.ndimage as nd

A = np.array([0,10,20,30,40,50,60,70,80,90])

Say you have a neighbor function:

def nbf(arr):
    return sum(arr)

To apply the neighbor function to every 5, with wrapped values at the edges:

C = nd.generic_filter(A, nbf, 5, mode='wrap')

print(C)
[200 150 100 150 200 250 300 350 300 250]