merge multiple files with similar column - perl

Question

I have 30 files where column 1 is similar in each file. I would like to join the files based on column 1 so that the output file contains column 2 from each of the input files. I know how to join two files, but struggle with multiple files.
join -1 1 -2 1 File1 File2
The files are tab-separated with no header like this
File1
5S_rRNA 1324
5_8S_rRNA 32
7SK 15
ACA59 0
ACA64 0
BC040587 0
CDKN2B-AS 0
CDKN2B-AS_2 0
CDKN2B-AS_3 0
CLRN1-AS1 0
File2
5S_rRNA 571
5_8S_rRNA 11
7SK 5
ACA59 0
ACA64 0
BC040587 0
CDKN2B-AS 0
CDKN2B-AS_2 0
CDKN2B-AS_3 0
CLRN1-AS1 0
Output
5S_rRNA 1324 571
5_8S_rRNA 32 11
7SK 15 5
ACA59 0 0
ACA64 0 0
BC040587 0 0
CDKN2B-AS 0 0
CDKN2B-AS_2 0 0
CDKN2B-AS_3 0 0
CLRN1-AS1 0 0

Answer 1

First memory is the problem as the file size increases.Second if the ordering of the content is not important this will work good.
#!/usr/bin/perl
use strict;
use warnings;
my %hash;
my ($key,$value);
my #files=<files/*>;
foreach(#files){
open my $fh, '<', $_ or die "unable to open file: $! \n";
while(<$fh>){
chomp;
($key,$value)=split;
push(#{$hash{$key}},$value);
}
close($fh);
}
for(keys %hash){
print "$_ #{$hash{$_}} \n";
}

Answer 2

Below code will give your desire output but it will take more memory when number of files will increase (as you said there are 30 files). By using sort it sort the hash in alphabetical order of its keys (will give the output in same order as you mentioned in question).
#!/usr/bin/perl
use strict;
use warnings;
my #files = qw| input.log input1.log |; #you can give here path of files, or use #ARGV if you wish to pass files from command line
my %data;
foreach my $filename (#files)
{
open my $fh, '<', $filename or die "Cannot open $filename for reading: $!";
while (my $line = <$fh>)
{
chomp $line;
my ($col1, $col2) = split /\s+/, $line;
push #{ $data{$col1} }, $col2; #create an hash of array
}
}
foreach my $col1 (sort keys %data)
{
print join("\t", $col1, #{ $data{$col1} }), "\n";
}
Output:
5S_rRNA 1324 571
5_8S_rRNA 32 11
7SK 15 5
ACA59 0 0
ACA64 0 0
BC040587 0 0
CDKN2B-AS 0 0
CDKN2B-AS_2 0 0
CDKN2B-AS_3 0 0
CLRN1-AS1 0 0