Off-by-One Errors

Comments discuss off-by-one errors in programming, focusing on array indexing conventions like zero-based vs one-based, negative indices, and related bugs in loops and slicing.

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MODDED df.loc StackOverflow IMO SET GET NextIndex i.e MRI array index indexing slice length indices indexes negative elements arrays

Sample Comments

PeterisP • Aug 15, 2014 • View on HN

What are the functional equivalents of off-by-one?

tracker1 • Nov 17, 2025 • View on HN

You forgot "Off by one errors."

RomanPushkin • Nov 20, 2022 • View on HN

You're my man! The only complaint is array index starts with 1. Can we break backwards compatibility please and make it 0?

_blk • Sep 11, 2023 • View on HN

Easy answer: the index of arrays doesn't start at 0

typon • Aug 9, 2018 • View on HN

Reading through the docs, looks like they have 1-indexed arrays..?

Mikhail_K • Jan 20, 2021 • View on HN

Negative indices are bug-prone. If you mess up iteration bounds, you should get an error, not silent incorrect indexing.

vages • Nov 23, 2025 • View on HN

Mind your off-by-1s: 97 items is not large, 98 is.

couchand • Jul 5, 2023 • View on HN

Maybe... or maybe it's got the same off-by-one error from the StackOverflow answer it's parrotting?

tomsaffell • May 10, 2016 • View on HN

zero-based indexing giving you an 'off by one' problem?

whamill • Apr 13, 2012 • View on HN

The scourge of the off-by-one error strikes again.