[Python] Expanding pandas based code that detect the frequency of the consecutive number to...

This stackoverflow answer provides a simple way (below) to find the frequency and indices of consecutive repeated numbers. This solution is much faster than loop-based code (see the original post above).

boundaries = np.where(np.diff(aa) != 0)[0] + 1 #group boundaries

get_idx_freqs = lambda i, d: (np.concatenate(([0], i))[d >= 2], d[d >= 2])
idx, freqs = get_idx_freqs(boundaries, np.diff(np.r_[0, boundaries, len(aa)]))


and the output

# aa=np.array([1,2,2,3,3,3,4,4,4,4,5,5,5,5,5])
(array([ 1, 3, 6, 10]), array([2, 3, 4, 5]))

# aa=np.array([1,1,1,np.nan,np.nan,1,1,np.nan])
(array([0, 5]), array([3, 2]))


Wondering if this solution could be expanded to work on multidimensional array instead of the slow traditional loop.

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