Perl: Replace many array element with another corresponding array element in a file

Question

I am trying to replace many array element with another corresponding array element in a file, but its taking ages to execute. Is there a simpler approach ? Below is my code:

open( my $in,  '<', "Test.txt")  or die "cannot open Test.txt $!";
open( my $out, '>', "TestFinal.txt") or die "cannot create TestFinal $!";
while( <$in>)
{ 
    for(my $i=2 ; $i<=$LastRowGlossary; $i++)
    {
        s/$variable[$i]/$vardescription[$i]/g;
    }
    for(my $j=2 ; $j<=$LastRowTable; $j++)
    {
        s/$COVERAGE_TYPE_CODE[$j]/$TCOVERAGE[$j]/g;
        s/$CVG_TEST_CRIT_CD[$j]/$TCVG_TEST_CRIT_TYP[$j]/g;
    }

    print {$out} $_;

}
close $in; 
close $out;

Please advise.

All the arrays elements are being picked up from an excel sheet. eg: $variable[2] contains "TEMP" $vardescription[2] contains "Temperature" and so on. And the size of each array goes upto 60 or maybe more. — Spooferman
– Spooferman, Commented Oct 17, 2012 at 12:02
You should probably use some precaution to avoid partial substitutions, such as CAR being replaced in CARCASS. — TLP
– TLP, Commented Oct 17, 2012 at 13:02

choroba · Accepted Answer · 2012-10-17 14:34:14Z

5

Sometimes, generating the regex can help:

#!/usr/bin/perl
use warnings;
use strict;

my @variables =    qw/a b c d e f g h/;
my @descriptions = qw/A B C D E F G H/;

my %replace;
@replace{@variables} = @descriptions;

my $string = 'xaxbxcxdxexfxgxhx';

my $pattern = '(' . join('|', map quotemeta, @variables) . ')';

$string =~ s/$pattern/$replace{$1}/g;

print "$string\n";

edited Oct 17, 2012 at 14:34

answered Oct 17, 2012 at 12:43

choroba

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2 Comments

Guru Over a year ago

Very nice one...learnt quite a few things in just a single post of yours..thank you..

Spooferman Over a year ago

@choroba I tried your approach. Really a good one! But still the time taken is same.. :(

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