Re^2: Sort problems

pack q{NNa*}, m{(\d+)_(\d+)}, $_

Note that packing with an 'N' specifier fails if either of the numeric fields exceeds 4294967295. An approach using sprintf (as mentioned in johngg's reply) can get around this.

>perl -wMstrict -le
"my @list = qw{ a1_2 a1_1 a10_10 a2_10 a2_1 a2_2 a10_1 a10_2 a1_10 };
 use constant WIDTH => 20;
 my @sorted =
    map { substr $_, WIDTH * 2 }
    sort
    map { sprintf '%0*4$d%0*4$d%s', m{(\d+)_(\d+)}, $_, WIDTH }
    @list;
 print for @sorted;
"
a1_1
a1_2
a1_10
a2_1
a2_2
a2_10
a10_1
a10_2
a10_10
[download]

Comment on Re^2: Sort problems Select or Download Code

Replies are listed 'Best First'.
Re^3: Sort problems by johngg (Canon) on Dec 03, 2008 at 10:22 UTC
Nice ++ I had never seen the `*4$` construct, used to grab arguments by position for printf/sprintf, before. Very useful. Thanks for pointing it out. Cheers, JohnGG	[reply] [d/l]
Re^3: Sort problems by monarch (Priest) on Dec 04, 2008 at 03:38 UTC
Where can I find an explanation for the extra formatting details that resulted in `'%04$d%04$d%s'` (I'd like to learn more about this myself). Has such support been around for a long time in Perl? Is it Perl-specific, or does the GNU C library now support such syntax?	[reply] [d/l]