Python: Combine array rows based on difference between prior row's last element and posterior row's first element -

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as title, given (n, 2) numpy array recording series of segment's start , end indices, example n=6:

import numpy np # x records (start, end) index pairs corresponding 6 segments x = np.array(([0,4],    # 1st seg ranges index 0 ~ 4               [5,9],    # 2nd seg ranges index 5 ~ 9, etc.               [10,13],               [15,20],               [23,30],               [31,40])) 

now want combine segments small interval between them. example, merge consecutive segments if interval no larger 1, desired output be:

y = np.array([0,13],    # cuz 1st seg's end close 2nd's start,                          # , 2nd seg's end close 3rd's start, combined.              [15,20],   # 4th seg away prior , posterior segs,                         # remains untouched.              [23,40])   # 5th , 6th segs close, combined 

so output segments turn out 3 instead of six. suggestion appreciated!

if we're able assume segments ordered , none wholly contained within neighbor, identifying gap between end value in 1 range , start of next exceeds criteria:

start = x[1:, 0]  # select columns, ignoring beginning of first range end = x[:-1, 1]  # , end of final range mask = start>end+1  # identify consecutive rows have great gap 

then stitching these pieces together:

np.array([np.insert(start[mask], 0, x[0, 0]), np.append(end[mask], x[-1, -1])]).t out[96]:  array([[ 0, 13],        [15, 20],        [23, 40]]) 

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