Simple perl counter

cosmicsoup has asked for the wisdom of the Perl Monks concerning the following question:

Hi Monks,

For many of you, this will be pretty simple, yet I'm having some problems putting this into code. I'm reading in a file.

open(IN, "<$file") || die "Can't open $file!\n";

while(<IN>) {
chomp($_);
my ($id, $stdate, $enddate, $person) = split(/\|\|/, $_);
}
[download]

There is a many to many relationship between $id and $person. I want to produce a list that has a count of id's for each person. It seems a hash would be the most likely way to do this. But I haven't been able to get it to work. Here is what I would like to produce for the output:

James P  24 id's
Alex S   50 id's
Diane G   4 id's
James A  12 id's
Sam D    11 id's
[download]

Any thoughts?

Louis

Comment on Simple perl counter Select or Download Code

Replies are listed 'Best First'.
Re: Simple perl counter by Abigail-II (Bishop) on Apr 21, 2004 at 13:52 UTC
`$ perl -aF'\\|\\|' -nle '$F {$F [3]} ++; END {printf "%s has %d id\x27s\n" => $_, $F {$_} for keys %F}' data` [download] Abigail	[reply] [d/l]
Re: Simple perl counter by matija (Priest) on Apr 21, 2004 at 13:18 UTC
Well, what have you tried? Counting the ids in the loop can be done with `$ids{$person}++;` and you can output the list with `foreach (keys %ids) { print "$_ $ids{$_} id\'s\n"; }` [download] Which of these two were you having trouble with?	[reply] [d/l] [select]
Re: Simple perl counter by Limbic~Region (Chancellor) on Apr 21, 2004 at 13:15 UTC
Louis, You will have to forgive me if this is wrong - my brain has been missing for the last couple of weeks (Philippines) and I just found it (back to work). `#!/usr/bin/perl use strict; use warnings; my $file = $ARGV[0] \|\| 'input.txt'; open (INPUT, '<', $file) or die "Unable to open $file for reading : $! +"; my %data; while ( <INPUT> ) { chomp; my @info = split /\\|\\|/; push @{$data{$info[3]}}, $info[1] if ! $data{$info[3]} \|\| ! grep / +^$info[1]$/ , @{$data{$info[3]}}; } for my $id ( keys %data ) { print "$id : " , scalar @{$data{$id}}, "\n"; }` [download] It assumes you only want unique ids counted - it is much easier if that is not the case : $data{$name}++ Cheers - L~R	[reply] [d/l]