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Re: Dictionary-style sort a la Tcl?

by moodster (Hermit)
on Apr 18, 2002 at 10:35 UTC ( #160166=note: print w/replies, xml ) Need Help??

in reply to Dictionary-style sort a la Tcl?

As an exercise, I wrote a new comparison routine for use with sort. It splits each string to be compared into parts and if two parts are both numbers, they will be compared numerically. Whitespace is ignored. A shorter string is considered smaller than a longer (that is, "abc" is smaller than "abcde" ).
sub dictcmp { my $ac = $a; my $bc = $b; while( 1 ) { my @a = $ac =~ /^\s*(([A-Za-z]+)|(\d+))(.*)/; my @b = $bc =~ /^\s*(([A-Za-z]+)|(\d+))(.*)/; return 0 if !defined $a[0] & !defined $b[0]; return -1 if !defined $a[0]; return 1 if !defined $b[0]; my $res; if( $a[0] =~ /\d+/ && $b[0] =~ /\d+/) { $res = $a[0] <=> $b[0]; } else { $res = $a[0] cmp $b[0]; } return $res if $res; $ac = $a[3]; $bc = $b[3]; } }
Calling this routine optimized would be a blatant lie, and I'm sure a lot of things can be improved. It does work, however, at least for simple input data:
my @list = ( "x10 y", "1abc", "a10y", "x9y", " b1" ); print join "\n", sort dictcmp @list;
1abc a10y b1 x9y x10 y


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