SPUG: sorting hierarchical section numbers
John W. Krahn
krahnj at telus.net
Thu Aug 10 23:59:07 PDT 2006
Michael R. Wolf wrote:
> I want to sort strings that represent outline numbers.
>
> 1
> 1.1
> 1.2
> 1.3
> 1.3.1
> 1.3.2
> 1.3.2.1
> 1.2
>
> I can't find a module. Could you point me in the correct direction so that
> I can read the fine manual? I can't seem to find the right search term;
> these are too general 'hierarchy', 'outline', 'number', 'sort'.
$ perl -le'
my @numbers = qw(
1
1.1
1.2
1.3
1.3.1
1.3.2
1.3.2.1
1.2
);
print for
map $_->[ 0 ],
sort { $a->[ 1 ] cmp $b->[ 1 ] }
map [ $_, pack q[C*], split /\./ ],
@numbers;
'
1
1.1
1.2
1.2
1.3
1.3.1
1.3.2
1.3.2.1
This should work as long as each individual number does not exceed 255, for
larger numbers use 'n*' and for really large numbers use 'N*' for the pack format.
John
--
use Perl;
program
fulfillment
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