[SciPy-user] indices of consecutive elements

I'm trying to figure out a way to return the indices of the start and end of a run of consecutive elements that match some condition, but only if there are more than a certain number. For example, take the array (with indices in comment for clarity): #0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 [0, 0, 1, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 1, 1, 0] I want to find the start and end indices of all runs of 1s with length of 4 or longer; so here the answer would be: [[2,5], [15,18]] Is there a reasonable way to do this without looping? I've been playing around with diff() and where() but without too much progress. Thanks, dan