• Files and I/O
• split

I see you have removed strictures (use strict; use warnings;) from the code NetWallah supplied, probably because they were telling you things you didn't understand and seem not to be bothered finding out about. So, rather than just giving you a solution to your problem, I want to see you do at least enough work to fix those errors. Show me the fixed code and I'll show you how to solve the rest of the problem.

I mentioned in the OP that I was still working on the code in order to get the output as I would like it to present. But here's the code in a proper format:

    use strict;
    use warnings;

    my @points = ( {X=>79.620,   Y=>54.720, Z=>53.034},
                   {X=>81.822,   Y=>54.071, Z=>50.027},
                   {X=>83.871,   Y=>51.966, Z=>52.424}, 
                   {X=>80.927,   Y=>49.712, Z=>53.305},
               {X=>80.565,   Y=>46.114, Z=>52.104},
                   {X=>77.173,   Y=>45.173, Z=>50.689},
                   {X=>75.652,   Y=>41.722, Z=>51.009});

    my @results;

    for my $x(0..$#points){
       my $p1 = $points[$x];
       for my $y (0..$#points){
        my $p2 = $points[$y];
        my $dist = sqrt(abs(( $p1->{X} - $p2->{X} ) **2
                 + ( $p1->{Y} - $p2->{Y} ) **2
                 + ( $p1->{Z} - $p2->{Z} ) **2)) ;  
        $results[$x][$y] = sprintf("%.0f", $dist);
       }
    }
    #-------------------

    for my $r (@results){
       printf "%.0f\t",$_ for @$r;
       print "\n";
     } 
[download]

/code

This may, at least, get you started:

use strict;
use warnings;

my $valuesFile = 'file.txt';
my (@points, $count);
my @keys = qw(A X Y Z);

open FH, $valuesFile or die "Can't open $valuesFile: $!";

while(<FH>){
    chomp;
    my %pointHash;
    $pointHash{$keys[$count++]} = $_ for (split)[0, 2..4];
    push @points, \%pointHash;
    $count=0;
}

close FH or die "Can't close $valuesFile: $!";

my @results;

for my $x(0..$#points){
   my $p1 = $points[$x];
   for my $y (0..$#points){
        my $p2 = $points[$y];
        my $dist = sqrt(abs(( $p1->{X} - $p2->{X} ) **2
                 + ( $p1->{Y} - $p2->{Y} ) **2
                 + ( $p1->{Z} - $p2->{Z} ) **2)) ;  
        $results[$x][$y] = sprintf("%.0f", $dist);
   }
 }
#-------------------

print "\t";
print "$points[$_]->{A}\t" for(0..$#points);
print "\n";

$count = 0;

for my $r (@results){
    print "$points[$count++]->{A}\t";
    printf "%.0f\t",$_ for @$r;
    print "\n";
 }
[download]

Output:

    A    B    C    
A    0    4    5    
B    4    0    4    
C    5    4    0
[download]

Hope this helps!

Your code calculates distance correctly, thank you. However, I think since I have a 360x360 matrix my output comes out weird when I transfer the data to a text file. Here's what it looks like:

      A B C 
    A 0 4 5
    4 3 4 3
    B 4 0 4
    6 4 4 3
    C 5 4 0
[download]

Any suggestions on how to correct this?

The code to calculate distance isn't mine; it was in your original code.

There may be some line wrapping going on in what you're showing. I created a 360x360 matrix and the results displayed fine.