Identify groups of continuous numbers in a list

Question

I\'d like to identify groups of continuous numbers in a list, so that:

myfunc([2, 3, 4, 5, 12, 13, 14, 15, 16, 17, 20])

Returns:

Answer 1

Assuming your list is sorted:

>>> from itertools import groupby
>>> def ranges(lst):
    pos = (j - i for i, j in enumerate(lst))
    t = 0
    for i, els in groupby(pos):
        l = len(list(els))
        el = lst[t]
        t += l
        yield range(el, el+l)


>>> lst = [2, 3, 4, 5, 12, 13, 14, 15, 16, 17]
>>> list(ranges(lst))
[range(2, 6), range(12, 18)]