How to check if a range is a part of another range in Python 3.x

Question

How can I simply check if a range is a subrange of another ?

range1 in range2 will not work as expected.

Answer 1

You can do it in O(1), as follows:

def range_subset(range1, range2):
    """Whether range1 is a subset of range2."""
    if not range1:
        return True  # empty range is subset of anything
    if not range2:
        return False  # non-empty range can't be subset of empty range
    if len(range1) > 1 and range1.step % range2.step:
        return False  # must have a single value or integer multiple step
    return range1.start in range2 and range1[-1] in range2

In use:

>>> range_subset(range(0, 1), range(0, 4))
True