Reverse a range

Reverse a range.

Expected output:

range(1, 10, 2) -> range(9, -1, -2)

range(1, 5, 1) -> range(4, 0, -1)

def reversed_range(start, stop=None, step=1):

    if stop is None:
        return range(start - step, -step, -step)
    else:
        new_start = stop - ((stop-start-1) % step + 1)
        new_end = new_start - (stop-start+step-1) // step * step
        if (stop - start) % step == 0 and step < 0:
            new_start -= step

    return range(new_start, new_end, -step)

# test
print(reversed_range(1, 10, 2))    # range(9, -1, -2)
print(reversed_range(1, 5, 1))     # range(4, 0, -1)

See also

https://gist.github.com/fcicq/ddb746042150b4e959e6 https://www.w3resource.com/python-exercises/math/python-math-exercise-71.php