Re^3: SQL like query over iterable in perl

Cute

Made me think $fields = [$fields,@_] unless ref fields;

and not that it matters here, and i would have to look up funny debug commands to tell for sure, but are $#$fields-1 and $fields->[-1] optimized or does the subtraction happen every loop of $obj? Im never sure.

and in mine, besides $data,$fields,and $count as nicer variable names, i had already decided i should have $size1 be named as $nterminal and $size2 named as $nsubparts to make it clearer what they did. wasnt gun'a post as a "fix" but this gave me an excuse to mention it.

Edited to add: What about missing fields? ~~$ref = $ref->{ $obj->{ $fields->[$_] // '.' } } //= {}~~ where '.' is used like the SAS missing variable.
That wasnt right, instead $ref = $ref->{ $obj->{ $fields->[$_] } // '.' } //= {}

Comment on Re^3: SQL like query over iterable in perl Select or Download Code

Replies are listed 'Best First'.
Re^4: SQL like query over iterable in perl by haukex (Archbishop) on Mar 02, 2017 at 13:06 UTC
I hope it's clear I wasn't being entirely serious or saying that my code was "better", it was just a lighthearted retort :-) i would have to look up funny debug commands to tell for sure, but are `$#$fields-1` and `$fields->[-1]` optimized or does the subtraction happen every loop I'm not sure either, but I'd have to guess no, since the optimizer would have to know for certain that `@fields` won't change, and in a language as dynamic as Perl, that's probably very rarely the case, if ever. As for the debug command, I assume you're thinking of B::Deparse, invoked as `perl -MO=Deparse script.pl`, which would show, for example, constant folding. I did a quick test with Benchmark and refactored out `$fields->[-1]` and `$#$fields-1` to before the loop, and that gave a consistent but small speed increase of ~5% (although IIRC, in terms of Benchmark results that's still in the margin of error of being insignificant). I didn't take missing fields into account because the OP was asking about objects, but you have a good point there, my code doesn't properly handle `undef` values (or an empty `@$fields` for that matter).	[reply] [d/l] [select]
Re^4: SQL like query over iterable in perl by pwagyi (Monk) on Mar 04, 2017 at 03:33 UTC
Actually I have quite similar function that dynamically creates nested hash counter. That gives confirmation that I'm in the right direction. :) Thanks.	[reply]