Re: Writing Program With Hashes and Loops For Files With Data in Columns

[arnaud99]

Hi,

I have looked at the code and I have written a program that could be used as a starting point for what you are trying to achieve.

This program does not cover all of what you are trying to do, it simply goes up to splitting the milcar file and loading a hash. I hope this gives you an idea of some perl's best practises (or what I would consider best practises), and help you complete your task.

Kind regards.

Arnaud

use strict; # Please use these 2 pragmas
use warnings;

use autodie; #this one comes handy as well

if (@ARGV !=4 ) {
    die "Ooops etc..";
}

    # a more descriptive name for your vars, otherwise you may as well
    # use $ARV[0], $ARGV[1] etc...
my ($milcar_filename, $check_file, $matches_file, $three_column_file) 
+= @ARGV;

#use the 3 args version of open;
open my $fh, '<', $milcar_filename; 
                #prg will 'die' if file error due to the autodie pragm
+a
    
    #store some values into a hash    
my %hash;        
while my $line(<$fh>) {
    chomp $line;

        # I assume here that the milcar file is pipe separated
        # but replace the separator with the separaor of your choice
    my ($last_name, $first_name, $integer1, $word1,
            $integer2, $word2, $real_number) = split /\|/, $line;

        #build a key, see if the key already exists, and
        # update with the latest int2 value, if larger.
    my $key = $last_name . '_' . $first_name;
    if (exists $hash{$key} ) {

           if ($integer2 > $hash{key} ) {
            $hash{$key} = $integer2;
        }
    }
    else {
        $hash{$key} = $integer2;
    }
}