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There is more than one path to take here:

  1. Zero-pad your numbers, so generate them with
    my $padded=sprintf("%08.3f",39.452);
    You can do this while reading your data:
    while (<>){ split /:/; $_[0]=sprintf("%08.3f", $_[0]); push @data, join ":", @_; }
  2. Or you can sort numerically. This requires you to extract the numbers and sort on them with <=> (see perlop), like
    sort{ $a <=> $b} @numbers;
    . You can write a sub for the extraction:
    sort{extract( $a ) <=> extract( $b )} @lines; sub extract{ $a = shift; split /:/, $a; $_[0]; }
  3. It's better to extract your numbers, and use them as keys in a hash, and work with a list of sorted keys:
    my %hash; while(<>){ my ($key, $data) = split( /:/, $_, 2 ); $hash{ $key } = $data; } print "Sorted!:\n\n", join "|", sort {$a <=> $b} keys %hash;
  4. .... many more paths to come up with


"We are not alone"(FZ)
(code untested, you'll get the idea)

Albannach is right of course. Still, if you have quite some data, a hash-lookup is more efficient. And more scalable, as you can tie your hash onto a database, e.g. To prevent that double-count problem, add a check in for the key, if a double, add a counter or something.

$key .= ':001' if defined $hash{$key}; $key++ while defined $hash{$key};

In reply to Re: Sorting an array of strings by number by jeroenes
in thread Sorting an array of strings by number by Anonymous Monk

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