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Re: compare two strings and return only he unique values.

by AnomalousMonk (Chancellor)
on Feb 04, 2013 at 01:57 UTC ( #1016886=note: print w/replies, xml ) Need Help??

in reply to compare two strings and return only he unique values.

Here's a substution-based version that may be somewhat along the lines Learnlot1 was thinking of originally. It does not generalize well to handling more than two strings as the split-to-hash approaches do. It suffers from the vagueness of the implied specification as other approaches do. But it works (for some definition of 'works').

>perl -wMstrict -le "for my $ar_vector ( [ qw(ABCDE BCDEO) ], [ qw(ABCDE BBBBB) ], [ qw(ABCDEA BCDEO) ], ) { my ($s1, $s2) = @$ar_vector; printf qq{'$s1' '$s2' -> '%s' \n}, non_common($s1, $s2); } ;; sub non_common { my ($sa, $sb) = @_; ;; (my $a_sans_b = $sa) =~ s{ [\Q$sb\E]+ }{}xmsg; (my $b_sans_a = $sb) =~ s{ [\Q$sa\E]+ }{}xmsg; return $a_sans_b . $b_sans_a; } " 'ABCDE' 'BCDEO' -> 'AO' 'ABCDE' 'BBBBB' -> 'ACDE' 'ABCDEA' 'BCDEO' -> 'AAO'

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[erix]: aka: create extension if not exists file_fdw;
[erix]: the annoying thing is that during setup of the 'foreign table' you have to specify all the columns. But that is reasonably automatable (just reading header line, and contruct the needed CREATE FOREIGN TABLE' statement)
[erix]: it may be easier to just slurp your fils into regular tables. Has other infrastructure advantages also (indexes, constraints etc)

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