a reoccurring problem for novice in perl

[szzxy]

Hi experts,
I have an input file with 2 columns (col_1 and col_2). The information in col_1 can occur more than once throughout the file, whereas the info on column 2 are all unique.
I tried to write a perl program to put all col2 info into one row when the col1 are the same.

...
##I have parsed my file
my $initial=0;
while(my $line=<file>){
if ($col_1 eq $initial ){
push(@table, $col_2);
$initial=$col_1;
} else {

}
}

What should I write in else? so that I can make another row for the $col_2 if the col_1 is different from the previous one?

Regards,
szsy




}
}

 

[Zhris]

Hi,

It would be best to use a hash structure, storing values in an array context:

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

my %hash = ();

while (my $line = <DATA>) {
	my ($name, $score) = split /\,\s/, $line; 
	push (@{$hash{$name}}, $score);
}

print "$_, ", join (', ', @{$hash{$_}}), "\n" foreach (keys %hash);


__DATA__
Chris, 6
Peter, 10
William, 14
Peter, 17
Lucy, 18
Peter, 19
Hayley, 20
Lucy, 40

Chris