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Re: How do I create a sort sub on-the-fly?

by japhy (Canon)
on Nov 02, 2001 at 20:02 UTC ( #122820=note: print w/replies, xml ) Need Help??

in reply to How do I create a sort sub on-the-fly?

Just so you know, require() doesn't happen until run-time, so I don't see the need for the BEGIN block. Anyway, here's how I would construct a sort function... maybe I love regexes too much?
# assume my(%field) exists, holding name->index pairs # assume my(@records) exists, holding your recods my $data = "lnum-a,source-a,hits-d,sip-d,time-a"; my %is_string = ( source => 1 ); # sort with cmp my $sorter = make_field_sort($data, \%field, \%is_string); for (sort $sorter @records) { ... } sub make_field_sort { my ($data, $FIELD, $STRING) = @_; my @cmp; for (split /,/, $data) { my ($f, $o) = split /-/; push @cmp, ('b <=> a', 'a <=> b')[$o eq 'a']; $cmp[-1] =~ s/<=>/cmp/ if $STRING->{$f}; $cmp[-1] =~ s/([ab])/\$${1}->[$FIELD->{$f}]/g; } local $" = " or "; eval "sub { @cmp }"; }

Jeff[japhy]Pinyan: Perl, regex, and perl hacker.
s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;

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