Re: How do I select first string of a two dimensional array to compare to other values?

[choroba]

Hi joi1369, welcome to the Monastery!

I don't understand your question. It's usually better to include sample input data (within <code> tags) and expected output.

If you want to work with the first line only, don't use while. If you want to compare two string values, you should use eq, ne, or index, or maybe a regex: $value =~ /\Q$important/.

Update: example script added:

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

my $first_line = <DATA>;
my $important = (split ' ', $first_line)[0];

while (<DATA>) { # Process the remaining lines.
    my $value = (split)[0];
    print if $value eq $important;
}

__DATA__
john chevrolet usa
hans bmw       germany
ivan lada      russia
john talbot    uk

[joi1369]

Thank you for the welcome! Let me try to clarify things a bit. This is the input-

1424621700, 2015-02-22 16:15:00, 4294.700
1424621760, 2015-02-22 16:16:00, 4289.700
1424621820, 2015-02-22 16:17:00, 4299.800
1424621880, 2015-02-22 16:18:00, 4302.800
1424621940, 2015-02-22 16:19:00, 4296.900
1424622000, 2015-02-22 16:20:00, 4301.000

I'm trying to run it through this script (fixed from above)-

#!/usr/bin/perl

use strict;
use warnings;

my $file = $ARGV[0];

open (RAW, "./$file") or die "Can't open $file for read: $!";
open (OUT, ">./OUTPUT_$file") or die "Can't open Output_$file: $!";

while(<RAW>) {

        my $line = $_;
        chop($line);
        next if ($line =~ /!/);
        my @splits = split (',', $line);

        my $first_line = $splits;
print "$first_line\n";
}

I am trying to get the string "1424621700" assigned to "$first_line" and then printed. Sorry about the disorganization. I'm new to Perl and haven't quite gotten the hang of it yet.

[AnomalousMonk]

So how does your current code fail to serve your purposes? An alternative:

c:\@Work\Perl\monks>perl -wMstrict -le
"my $line = qq{1424621700, 2015-02-22 16:15:00, 4294.700\n};
 chomp $line;
 print qq{'$line'};
 ;;
 my ($first) = split m{ , \s* }xms, $line;
 print qq{'$first'};
"
'1424621700, 2015-02-22 16:15:00, 4294.700'
'1424621700'

Update: Ah, I see it now:
    my $first_line = $splits;
and again, how can this compile with strict enabled? You probably want something like the
    my $first_line = $splits[0];
statement you had before.

[joi1369]

Rather than printing out only 1424621700, it prints out the entire first column like so-

1424621700
1424621760
1424621820
1424621880
1424621940
1424622000
1424622060
1424622120
1424622180
1424622240
1424622300

Again, thank you so much for the help