Re: Numeric sorting WITHOUT <=>

[Marshall]

in reply to Numeric sorting WITHOUT <=>

If you want to sort by a numeric value, using the "spaceship" operator "<=>" is THE way to go!

If you sort by "ascii order" on a numeric field, then you have to have the same number of "ascii digits" or the sort will not work.

!/usr/bin/perl -w
use strict;

my %jetsons = (
    7  => 'Judy',
    10 => 'Jane',
    11 => 'George',
    2  => 'Elroy',
    100=> 'Rosey',
    1  => 'Astro',
    19 => 'Mr. Spacely',
    22 => 'Mr. Cogswell');

foreach my $key (sort { $a<=>$b } keys %jetsons)
{
   printf "%-5s %s\n", $key, $jetsons{$key};
}

__END__
1     Astro
2     Elroy
7     Judy
10    Jane
11    George
19    Mr. Spacely
22    Mr. Cogswell
100   Rosey

Use <=> to compare numeric values.
Use cmp to compare string values.

I often advocate date/time strings like this: 2010-10-03 0837
A string like that (YYYY-MM-DD HHMM) with leading zeros, can be compared against other date/times in a simple way (ASCII sort), but the leading zeroes are important! A simple ASCII sort order will work, but ONLY if the fields are of constant width and have leading zeroes.