range_finder.py

x = [5, 10, 15, 20, 30, 40, 50, 60, 100, 140]

def range_finder(seq):
    it = iter(seq)
    prev = next(it)
    prev_diff = seq[1] - seq[0]
    r = 0
    for (i, item) in enumerate(it):
        diff = item - prev
        if diff != prev_diff:
            print("range step {} of len {}".format(prev_diff, r))
            prev_diff = diff
            r = 0
        prev = item
        r += 1
        # emit final range
        if i == len(seq) - 2:
            print("range step {} of len {}".format(prev_diff, r))

range_finder(x)