Re: How can I do a numeric sort on a substring?

The general case would be to use a Schwartzian Transform but in this simplistic case for small values of n you can just perform the extractions within the sort:

use strict;
use warnings;

use Test::More tests => 1;

my @in   = qw/a-3 a-1 a-2/;
my @want = qw/a-1 a-2 a-3/;

my @have = sort { ($a =~ /(\d+)/)[0] <=> ($b =~ /(\d+)/)[0] } @in;
is_deeply \@have, \@want;
[download]

See also the FAQ: How do I sort an array by (anything)?

PS. Here's the same thing but with substr:

use strict;
use warnings;

use Test::More tests => 1;

my @in   = qw/a-3 a-1 a-2/;
my @want = qw/a-1 a-2 a-3/;

my @have = sort { substr ($a, 2) <=> substr ($b, 2) } @in;
is_deeply \@have, \@want;
[download]

🦛

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Re^2: How can I do a numeric sort on a substring? by misterperl (Pilgrim) on Jun 25, 2021 at 14:01 UTC
TYVM that's very helpful. Is the [0] there in case there are more than one number matching like a-1-3 ? TY!	[reply]
Re^3: How can I do a numeric sort on a substring? by haukex (Archbishop) on Jun 25, 2021 at 14:07 UTC
in case there are more than one number matching like a-1-3 ? Do you mean something like Sort::Key::Natural? See also How do I do a natural sort on an array?	[reply]
Re^4: How can I do a numeric sort on a substring? by LanX (Saint) on Jun 25, 2021 at 16:48 UTC
Thanks for pointing to Sort::Key , seems it covers all use cases of the Schwartzian transform with a short syntax. :) The documentation could be simpler tho, by deconstructing the naming convention. `[\|r][\|n\|i\|u]keysort[_inplace] @array` (Like this the doc seem even to be not logical/ wrong in one case) Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery}	[reply] [d/l]
Re^4: How can I do a numeric sort on a substring? by misterperl (Pilgrim) on Jun 25, 2021 at 14:15 UTC
sort key natural IS DA BOMB!! TY TY this made my week :)	[reply]
Re^4: How can I do a numeric sort on a substring? by misterperl (Pilgrim) on Jun 25, 2021 at 14:09 UTC
I never saw that Natural sort- you are on fire today all ++ votes! TYVM Have a great weekend- I'm headed off to study your suggestions..	[reply]
Re^5: How can I do a numeric sort on a substring? by BillKSmith (Monsignor) on Jun 25, 2021 at 15:56 UTC
Re^6: How can I do a numeric sort on a substring? by salva (Canon) on Jun 28, 2021 at 09:25 UTC
Some notes below your chosen depth have not been shown here
Re^3: How can I do a numeric sort on a substring? by hippo (Bishop) on Jun 25, 2021 at 15:12 UTC
Not specifically. The regex match is context sensitive, so the brackets around it enforce list context and then the `[0]` pulls out the first value of that list before the `<=>` gets a chance to enforce scalar context on it. Example: `#!/usr/bin/env perl use strict; use warnings; use feature 'say'; my $x = 'a-9'; say "Scalar: " . $x =~ /(\d+)/; say "List: " . ($x =~ /(\d+)/); say "First: " . ($x =~ /(\d+)/)[0];` [download] Read lots more in the Context tutorial. 🦛	[reply] [d/l] [select]


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