Dear Monks,
I'm dealing with some csv-files that I use as a basis to make various calculations. It all works fine and the calculations are correct except that while using: 
#!/usr/bin/perl -w # use warnings
use strict;
use diagnostics;

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I remain having the problem that I frequently get the message:
Use of uninitialized value in numeric eq (==) at
The reason for these warnings are probably 'missing values' in the csv-file. $_ will be undefined as I understood from documentation. While using things like (as mentioned in an earlier post):
use Data::Table;
$joinTable->colsMap( sub { $_->[4]  = skipblanks( $_->[4] ) } );

sub skipblanks {
    my @data = @_;
    my $x    = 0;
    foreach $x (@data) {
        if ($x) {
            $x =~ s/,/\./g;
        }
        return $x;
    }
}

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or 
use Data::Table;
$joinTable->colsMap( sub { $_->[4]  = to_int_or_zero( $_->[4] ) } );

sub to_int_or_zero {
    my $value = shift;
    if (
        defined($value)
        && (   $value =~ m/^\d+$/
            || $value =~ m/^-?\d+\.?d*$/ )
      )
    {
        return $value;
    }
    else {
        return 0;
    }
}

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The message is still appearing sometimes. What am I doing wrong? Maybe not ideal in every situation but what would work for me is to fill all blanks with '0' (zeroes). Is there a way to do this for the whole csv-file at the beginning of the script. Or maybe some other straightforward or generic way to make $_ always initialized in order to avoid the warnings?
Thanks,
Gert

In reply to avoid uninitialized values for $_ by GertMT

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