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Re: compare two files by column and return second (matching) column

by Kenosis (Priest)
on Aug 06, 2012 at 20:36 UTC ( #985828=note: print w/ replies, xml ) Need Help??


in reply to compare two files by column and return second (matching) column

Excellent suggestions have been given. Here's another option:

use Modern::Perl; open my $fhA, '<', 'FileA.txt' or die $!; my %hash = map { /(.+)\t(.+)/; $1 => $2 } grep /\S/, <$fhA>; close $fhA; open my $fhB, '<', 'FileB.txt' or die $!; say for map { chomp; $hash{$_} } grep /\S/, <$fhB>; close $fhB;

Output:

zzzzz bbbbb xxxxx

The first map uses a regex to grab the key/value pairs from FileA for placement into %hash. The second map uses the single entry from FileB to show that entry's associated value from FileA. Since there were blank lines in the files (from your data set), grep /\S/ was used to filter those.

Hope this helps!


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Re^2: compare two files by column and return second (matching) column
by ejbiers (Initiate) on Aug 07, 2012 at 13:45 UTC

    This is perfect! Thanks! However, is there a way to print the results into an output file?

      You're most welcome, ejbiers! Yes, the script below includes printing the results to a file:

      use Modern::Perl; open my $fhA, '<', 'FileA.txt' or die $!; my %hash = map { /(.+)\t(.+)/; $1 => $2 } grep /\S/, <$fhA>; close $fhA; open my $fhB, '<', 'FileB.txt' or die $!; my @output = map { chomp; $hash{$_} } grep /\S/, <$fhB>; close $fhB; open my $fhO, '>', 'Output.txt' or die $!; say $fhO $_ for @output; close $fhO;

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