Question

I have been learning Perl for a few days and I am completely new.

The code is supposed to read from a big file and if a line contains “warning” it should store it and print it on a new line and also count the number of appearances of each type of warning. There are different types of warnings in the file e.g “warning GR145” or “warning GT10” etc.

So I want to print something like

Warning GR145 14 warnings
Warning GT10  12 warnings

and so on

The problem is that when I run it, it doesnt print the whole list of warnings.
I will appreciate your help. Here is the code:

use strict;
use warnings;

my @warnings;

open (my $file, '<', 'Warnings.txt') or die $!;

while (my $line = <$file>)  {
  if($line =~ /warning ([a-zA-Z0-9]*):/) {
    push (@warnings, $line);
    print $1 ,"\n";
  }
}

close $file;

Answer 1

You need to use a hash array, a mapping from warning string to occurrence count.

use strict;
use warnings;

my %warnings = {};

open (my $file, '<', 'Warnings.txt') or die $!;
while (my $line = <$file>)  {
    if ($line =~ /warning ([a-zA-Z0-9]*)\:.*/) {
        ++$warnings{$1};
    }
}
close $file;

foreach $w (keys %warnings) {
    print $w, ": ", $warnings{$w}, "\n";
}