.csv file - problem with data manipulation

[mojo]

Hello all;
I'm having trouble with my perl script and need some guidance. I am able to read data from a .csv file using the script and am placing it into an array @field. The data consists of four columns. I'm using the first column $field[0] and the fourth column $field[3], and placing that into a hash.

My problem is that I want to be able to use the data in $field[1], to reference the keys in the hash. $field[0] consists of number 1 - 4, and $field[1] consist of number 1-4 in random order.

I want my output to be the data in $field[3] corresponding to $field[0] (its row).

I've tried looping through the hash using :
while (($key,$value) = each(%hash), and have only been successful to output the data in $field[3] when $key is "= =" to $field[1].

Hope I explained the problem well enough, if any further explanation is necessary please let me know. I also have a portion of my code it necessary.

Thanks

[numberwhun]

It would be a huge help if you could do two things:

1. Provide us with your script, as you have it so far. This will allow us to see all of your code, including modules that you may be using.
2. A sample of the file you are parsing with the script so we can see the data in question as well. Even if you don't post real data, it should be in the format the real data is.

Thanks!

Jeff

[mojo]

Sure no problem, just to warn you the code is a little messy because I've tried so many things, most of it is commented out just incase I need to reference back to it:

The data im using looks similar to this, but this is an example:

column 1 column 2 column 3
1 3 dog
2 2 cat
3 4 mouse
4 1 hat

I want the output to be outputed to a .csv file and look like this:

column 1 column 2 column 3 column 4
1 3 dog mouse
2 2 cat cat
3 4 mouse hat
4 1 hat dog

Thanks

#!/usr/bin/perl
#use warnings;
 
open(INFILE,"perl_data.csv") || die ("Could not open file");
open(OUT, ">test.csv") || die("Could not write file");
open(IN, "test.csv") || die("Could not open file");
 
 
my @field =(0);
my $field;
 
my @created_array = (0 .. 4);
 
while (<INFILE>) {
    s/\n//;
    @field =split(",");
 
    my %hash = ($field[0],$field[3]);
 
 
#    while ( my ($key, $value) = each(%hash) ) {
#        $key = $field[1];
#        if ($key != $field[0] || $key = $field[1]) {
#            print "$key => $value\n";
#        }
#    }
 
#    foreach my $key (keys %hash) {
#        print "$key = $hash{$key};
#    }
 
#    my $feature;
#    my @test_array = <IN>;
#    print "$field[1]\n";
#    foreach $value (@created_array) {
#        my $value = $hash{@created_array};
#        print $value;
#    }
 
#    print "$field[0][0]\n";
#    foreach my $key (keys %hash) {
#        print "$key = $hash{$key}\n";
#    }
 
#    foreach ($
#        print "$#field";
#        test_array = split(",");
 
#    foreach my $key (keys %hash) {
#        $key = $field[1];
#        print "$key = $hash{$key}\n";
#    }
#    foreach ($field[1]) {
#        print OUT "$field[1]", ",";
#    }
 
#    if ($field[1] > 0) {
#        my $field1 = $compare{$field[1]};
#        print "$field1\n";
#    }
#    print "$field[1]";
 
#    my @field1 = $compare{$field[1]};
#    print "@field1";
#    print "$field[1]";
}
close (INFILE);
 

Thanks

[mojo]

Sorry about the mess heres a better idea of what im trying to do :

#!/usr/bin/perl
#use warnings;
 
open(INFILE,"perl_data.csv") || die ("Could not open file");
open(OUT, ">test.csv") || die("Could not write file");
open(IN, "test.csv") || die("Could not open file");
 
my @field =(0);
my $field;
my @column1=(0);
while (<INFILE>) {
    s/\n//;
 
    @field =split(",");
    my %hash = ($field[0],$field[3]);
    while ((my $key, my $value) = each(%hash)) {
        if($field[1] != $field[0]) {
            $key = $field[1];
            print "$field[0]","$field[1]","field[3]", "$hash{$key}\n"
        } else {
            print "$field[0]","$field[1]","field[3]", "field[3]\n"
        }
    }
 

when I do this though only the data that match in column one and column two work..

[KevinADC]

You may need to follow this up with a tutorial in regards to references.

use warnings;
use strict;
#use Data::Dumper;
my %hash;
open(IN,"data.csv") || die ("Could not open file");
while(<IN>){
   chomp;
   my @t = split(/,/);
   $hash{$t[0]} = { parent => $t[2], child => $t[1] }; 
}
close(IN);
#print Dumper \%hash;
foreach my $key (sort {$a <=> $b} keys %hash) {
   print join(',', $key,
                   $hash{$key}{child},
                   $hash{$key}{parent},
                   $hash{$hash{$key}{child}}{parent} );
   print "\n";
}

I used "parent" and "child" really for my own benefit in figuring this out. No implication of a parent/child relationship is being implied, although there is similarity to a parent/child tree structure. Hopefully your real data is also applicable to this type of data structure.

The first three tutorials on this page discuss references:

http://perldoc.perl.org/index-tutorials.html

[mojo]

Thanks for the advice,I almost have the program working Now the problem is when I print the line I get the wrong output heres the code thus far:

open(INFILE,"perl_data.csv") || die ("Could not open file");
open(OUT, ">test.csv") || die("Could not write file");
open(IN, "test.csv") || die("Could not open file");
 
$counter =1;
while(<INFILE>) {
    chomp;
    (@data1[$counter],@data2[$counter],@data3[$counter],@data4[$counter])= split(/,/);
    $counter++;
}
close(INFILE);
 
for (my $i = 1; $i <= $#data1; $i++) {
    $n = @data2[$i];
    if(@data3[$i] >= .5) {
        print @data4[$n],@data4[$i],"\n";
        #print $data4[$i];#," ",@data4[$i]," ",@data1[$i],@data2[$n], "\n";
    }
}
 

it wont let have @data4[$n] and @data[$i] on the same line???
I want it to print

boat cat ... but its not letting me print boat if i want cat also on the same line????

[KevinADC]

can't help without seeing the data you are using in your latest code.