Ohke, so I now have this

open (A1, "<An1.txt") or die "can't open";
open (A2, "<An2.txt") or die "can't open";

my @array1;
my @array2;

while (<A1>)
{
    my $in = $_;
    chomp $in;
    push (@array1, [split(//, $in)]);
}

while (<A2>)
{
    my $in = $_;
    chomp $in;
    push (@array2, [split(//, $in)]);
}

my $length = $#array1;
my $total = 0;
for (my $x = 0; $x <= $length; $x++)                                  
+    
{
    my $smallLength = scalar(@{$array1[$x]});
    for(my $q = 0; $q <= $smallLength; $q++)
    {   
        if($array1[$x][$q] =~ /^(\+|\_)$/ && $array2[$x][$q] =~ /^[A-Z
+a-z]$/)                    
        {
            splice(@{$array2[$x]}, $q, 0, ''); 
        }
        
        if($array2[$x][$q] =~ /^(\+|\_)$/ && $array1[$x][$q] =~ /^[A-Z
+a-z]$/)                    
        {                                                             
+        
            splice(@{$array1[$x]}, $q, 0, ''); 
        }
        $total++;
    }
}

[download]

I am trying to compare and calculate the diffence between to text files. Calculations come later in my code but that is not important. I get error message 'Use of uninitialized value in pattern match (m//)' for the 2 IF statements. Any idea why?

In reply to Re^4: Parse txt file into array of array by Dr Manhattan
in thread Parse txt file into array of array by Dr Manhattan

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.