> If I saw that in a code review I'd flag it for non-obviousness. One should
> use 'string != new_string' unless there is severe pressure to squeeze
> every nanosecond out of this particular code (and it better be inside an
> inner loop).
I thought that someone had suggested that such things go in the PEP,
I'm sure someone did.
I think that may have been me in a tangent thread where folks were worried about O(N) checks on long strings.
I know at least I temporarily forgot to account for string equality checks starting with a few O(1) checks to speed up common cases (IIRC: identity, length, first code point, last code point), which means explicitly calling len() is just as likely to slow things down as it is to speed them up.
Cheers,
Nick.