CODEWITHSUNDEEP
perlhash
user2320229
user2320229

Reputation: 71

How to compare two hashes

I have two files I have read into 2 seperate hashes. The first file has two columns and looks like:

123456789 11111
234567891 22222
345678912 33333

The second file has one column, which looks like:

123456789
010124561
100324531

I want to compare the two hashes and whenever there is a match between the first columns of the two files, it should print to a new file with the results of the first column. This is what I have so far...

#!/usr/bin/perl

use Sys::Hostname;
use lib "$ENV{HOME}/common/lib/perl";
use strict;
use warnings;

my %oid;
my %oid2;
my %atom;
my %newline;
my $oid;
my $atom;
my @line  = ();
my @line2 = ();
my @oid   = ();
my @oid2  = ();

my $input  = 'file.txt';
my $input2 = 'file2.txt';
my $output = 'outputfile.txt';

open (IN, "<$input");
open (IN2, "<$input2");
open (OUT, "+>$output");

for my $line (<IN>) {
    chomp $line;
    my @line = split /\t/, $line;
    push( @oid, $line[0] );
    $oid{ $line[0] }  = $line[0];
    $atom{ $line[0] } = $line[1];
}

for my $line2 (<IN2>) {
    chomp $line2;
    my @line2 = split /\t/, $line2;
    push( @oid2, $line2[0] );
    $oid2{ $line2[0] } = $line2[0];
}

Upvotes: 2

Views: 257

Answers (2)

daxim
daxim

Reputation: 39158

Too much code. Know your Unix toolbox!

comm -12 <(cut -d' ' -f1 file1|sort) <(sort file2)

Upvotes: 2

Guru
Guru

Reputation: 16974

One way:

#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;
$\="\n";

open my $fh1, '<', 'f1' or die $!;
open my $fh2, '<', 'f2' or die $!;
my %h1;
while (<$fh1>){
        chomp;
        my ($x,$y)=split;
        $h1{$x}=$y;
}

while(<$fh2>){
        chomp;
        print if exists $h1{$_};
}

Upvotes: 1

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