Nested range Bug

[chlovec]

Bug report

Bug description:

def nested_range_bug(self, word: str) -> int:
        word_len: int = len(word)
        for left in range(len(word) - 1, - 1, -1):
            for index in range(1, min(10, word_len - left)):
                return left

    def test_my_word(self) -> None:
        actual_left = self.nested_range_bug("band")
        self.assertEqual(3, actual_left)

When using a nested range in two nested loops and the range in the inner loop is started at one, python skips processing of the the first iteration of the outer loop.
In the code example above, it's nested_range_bug is expected to return 3 but it returns 2 instead.

CPython versions tested on:

3.12

Operating systems tested on:

macOS

[tomasr8]

The first iteration of the outer loop is not skipped, it is actually the inner loop that is skipped because
range(1, min(10, word_len - left)) evaluates to range(1, min(10, 4 - 3)) which is range(1, 1) which is empty, so the inner loop does not run for the first iteration of the outer loop. It runs only on the second interation when left is 2 which is also the value that is returned from the function :)

[chlovec]

Thanks for the explanation.

…

On Sat, Oct 5, 2024 at 5:05 PM Tomas R. ***@***.***> wrote: The first iteration of the outer loop is not skipped, it is actually the inner loop that is skipped because range(1, min(10, word_len - left)) evaluates to range(1, min(10, 4 - 3)) which is range(1, 1) which is empty, so the inner loop does not run for the first iteration of the outer loop. It runs only on the second interation when left is 2 which is also the value that is returned from the function :) — Reply to this email directly, view it on GitHub <#125016 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/BIC5ARC3VYP7ZE2LMU5UJ23Z2B5E5AVCNFSM6AAAAABPNYIG4OVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDGOJVGIZTEMBUGM> . You are receiving this because you authored the thread.Message ID: ***@***.***>