http://www.perlmonks.org?node_id=1001476


in reply to Replacement of data in a column of a file using Hashes created from another file

The reason why it is slow is you use the nested loops (for each line, you loop over all the keys). The following code generates a regular expression that will match all the keys, so it saves you one loop: 
#!/usr/bin/perl
use warnings;
use strict;

open my $EQ, '<', '1.txt' or die "1: $!";
my %subst;
while (<$EQ>) {
    chomp;                                   # <- updated
    my ($search, $replace) = split /=/;
    $subst{$search} = $replace;
}

my $regex = join '|', map quotemeta, keys %subst;

open my $LST, '<', '2.txt' or die "2: $!";
while (<$LST>) {
    s/($regex)/$subst{$1}/;
    print;
}

[download]
لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ
  • Comment on Re: Replacement of data in a column of a file using Hashes created from another file
  • Download Code

Replies are listed 'Best First'.
Re^2: Replacement of data in a column of a file using Hashes created from another file
by rohitmonk (Initiate) on Oct 30, 2012 at 09:43 UTC

    Thank you for the reply. But I need to get an output file, I am pretty new to this syntax.

    And this output which gets printed does not have any replacements in it when i run it. Where is it searching for the hash-key and replacing it with the value?

[reply]

      Not sure what you mean:

      Input:

      10_25_res.txt:Locus3034v1rpkm4.98 gi|315134697|dbj|AP012030.1| 100.00 
+280 0 0 1 280 3402569 3402290 4e-140 506
10_25_res.txt:Locus3034v1rpkm4.98 gi|315134697|dbj|AP012030.1| 99.64 2
+80 1 0 1 280 227880 228159 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|315134697|dbj|AP012030.1| 99.64 2
+80 1 0 1 280 2704973 2704694 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|315134697|dbj|AP012030.1| 99.64 2
+80 1 0 1 280 4018745 4019024 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|315134697|dbj|AP012030.1| 99.64 2
+80 1 0 1 280 4149866 4150145 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|315134697|dbj|AP012030.1| 99.64 2
+80 1 0 1 280 4191268 4191547 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|315134697|dbj|AP012030.1| 98.93 2
+80 3 0 1 280 3924929 3925208 9e-136 491
10_25_res.txt:Locus3034v1rpkm4.98 gi|260447279|gb|CP001637.1| 100.00 2
+80 0 0 1 280 459101 459380 4e-140 506
10_25_res.txt:Locus3034v1rpkm4.98 gi|260447279|gb|CP001637.1| 99.64 28
+0 1 0 1 280 1156698 1156977 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|260447279|gb|CP001637.1| 99.64 28
+0 1 0 1 280 3643499 3643220 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|260447279|gb|CP001637.1| 99.64 28
+0 1 0 1 280 4302307 4302028 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|260447279|gb|CP001637.1| 99.64 28
+0 1 0 1 280 4343709 4343430 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|260447279|gb|CP001637.1| 99.64 28
+0 1 0 1 280 4474830 4474551 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|260447279|gb|CP001637.1| 98.93 28
+0 3 0 1 280 4568646 4568367 9e-136 491

      [download]

      Output:

      10_25_res.txt:Locus3034v1rpkm4.98 gi|315134697|dbj|AP012030.1| Escheri
+chia coli DH1 (ME8569) DNA,...
 100.00 280 0 0 1 280 3402569 3402290 4e-140 506
10_25_res.txt:Locus3034v1rpkm4.98 gi|315134697|dbj|AP012030.1| Escheri
+chia coli DH1 (ME8569) DNA,...
 99.64 280 1 0 1 280 227880 228159 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|315134697|dbj|AP012030.1| Escheri
+chia coli DH1 (ME8569) DNA,...
 99.64 280 1 0 1 280 2704973 2704694 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|315134697|dbj|AP012030.1| Escheri
+chia coli DH1 (ME8569) DNA,...
 99.64 280 1 0 1 280 4018745 4019024 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|315134697|dbj|AP012030.1| Escheri
+chia coli DH1 (ME8569) DNA,...
 99.64 280 1 0 1 280 4149866 4150145 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|315134697|dbj|AP012030.1| Escheri
+chia coli DH1 (ME8569) DNA,...
 99.64 280 1 0 1 280 4191268 4191547 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|315134697|dbj|AP012030.1| Escheri
+chia coli DH1 (ME8569) DNA,...
 98.93 280 3 0 1 280 3924929 3925208 9e-136 491
10_25_res.txt:Locus3034v1rpkm4.98 gi|260447279|gb|CP001637.1| Escheric
+hia coli DH1, complete genome
 100.00 280 0 0 1 280 459101 459380 4e-140 506
10_25_res.txt:Locus3034v1rpkm4.98 gi|260447279|gb|CP001637.1| Escheric
+hia coli DH1, complete genome
 99.64 280 1 0 1 280 1156698 1156977 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|260447279|gb|CP001637.1| Escheric
+hia coli DH1, complete genome
 99.64 280 1 0 1 280 3643499 3643220 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|260447279|gb|CP001637.1| Escheric
+hia coli DH1, complete genome
 99.64 280 1 0 1 280 4302307 4302028 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|260447279|gb|CP001637.1| Escheric
+hia coli DH1, complete genome
 99.64 280 1 0 1 280 4343709 4343430 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|260447279|gb|CP001637.1| Escheric
+hia coli DH1, complete genome
 99.64 280 1 0 1 280 4474830 4474551 2e-138 500
10_25_res.txt:Locus3034v1rpkm4.98 gi|260447279|gb|CP001637.1| Escheric
+hia coli DH1, complete genome
 98.93 280 3 0 1 280 4568646 4568367 9e-136 491

      [download]

      The replacement is done in the s/($regex)/$subst{$1}/ statement, and you can direct the output to a file by: 

      ./program.pl > output_file.txt

      [download]
      There does appear to be a stray carriage return in the output - the code may needs a chomp somewhere...
[reply]
[d/l]
[select]
        True, thank you. chomp added to the code. I did not notice because the format is not familiar to me and the expected output was not included to diff against.
        لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ
[reply]

        Hi, Try this one

        use strict;
use warnings;

my ($a, $b, $c) = @ARGV;

open(FILE, "$a");
my $text=do {local $/; <FILE>};
close FILE;

my %mymatch = $text =~ m/^\s*(.*?)\s*\=\s*(.*?)\s*$/igm;

open(FILE, "$b");
my $maintext=do {local $/; <FILE>};
close FILE;

foreach my $myfnd (sort {length($b) <=> length($a)} keys %mymatch) {
    $maintext =~ s/\Q$myfnd\E/$mymatch{$myfnd}/ig;
}

open(FILE,">$c");
print FILE $maintext;
close FILE;

        [download]
[reply]
[d/l]

        Thanks a ton Choroba

[reply]

        Thank you so much for looking into the problem and helping me out. Cheers... <\p>

[reply]
Re^2: Replacement of data in a column of a file using Hashes created from another file
by rohitmonk (Initiate) on Oct 31, 2012 at 05:46 UTC

    Thank you for the code, it was dope. Cool skills u got, wish to learn more. Cheers....

[reply]

In Section Seekers of Perl Wisdom