RE: How to sum up values

[Andrew Curry]

Something as crude as 

use Data::Dumper;
open( FILE, '< file' )
  || die $!;
  my ( $line, $ela, $elb, $pre, %count, $i, $tot); $tot = 0; 
  while ( $line = <FILE> ) {
        $i++;
        ( $ela, $elb ) = split ( '\|', $line );

        #
        # remove any white space
        #

        $elb=~s/\s+$//g;
        $elb=~s/^\s+//g;

        #
        # dont do the first element as will always
        # be different
        #

        if ( ( $ela ne $pre ) && $i != 1 ) {
                $count{$pre} = $tot;
                $tot = 0;
                $tot += $elb;
        }
        else {
                $tot += $elb;
        }
                $pre=$ela;
}

#
# get the final row total
#
$count{$pre} = $tot;
print Dumper(\%count);

Will probably do the job 

-----Original Message-----
From: Andrej Kastrin [mailto:[EMAIL PROTECTED] 
Sent: 24 April 2007 12:34
To: beginners@perl.org
Subject: How to sum up values

Dear all,

Question about the sum function; the file structure is as follows:

A|100
A|200
A|150
B|20
B|90
C|10
C|30
C|300

The result I want to obtain is to sum values in the second column
(columnB) for each particular letter in the first column (ColumnA); e.g.:

A|450
B|100
C|330

I don't want to use hash structure because the input file is very large. 
Is there any simple way to do that step-by-step: to sum up values in columnB
until the letter in columnA changes and print the result...

Thanks in advance for any suggestion, Andrej


#!/usr/bin/perl
use strict;
use warnings;
 
open FH1, "< test.txt" or die "Can't open file : $!"; while (<FH1>) {
    chomp;
    ($columnA,$columnB)=split /\|/;
    ... ???
}

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