Question

I m still in here. 😉
I’ve got this code from a very expert guy, and I’m shy to ask him this basic questions…anyway this is my question now; this Perl Script prints the median of a column of numbers delimited space, and, I added some stuff to get the size of it, now I’m trying to get the sum of the same column. I did and got not results, did I not take the right column? ./stats.pl 1 columns.txt
#!/usr/bin/perl

use strict;
use warnings;

my $index = shift;
my $filename = shift;
my $columns = [];

open (my $fh, "<", $filename) or die "Unable to open $filename for reading\n";

for my $row (<$fh>) {

my @vals = split/\s+/, $row;
push @{$columns->[$_]}, $vals[$_] for 0 .. $#vals;
}

close $fh;

my @column = sort {$a <=> $b} @{$columns->[$index]};

my $offset = int($#column / 2);
my $length = 2 - @column % 2;

my @medians = splice(@column, $offset, $length);

my $median;
$median += $_ for @medians;
$median /= @medians;

print "MEDIAN = $median\n";
################################################
my @elements = @{$columns->[$index]};
my $size = @elements;
print "SIZE = $size\n";
exit 0;
#################################################
my $sum = @{$columns->[$index]};
for (my $size=0; $size < $sum; $size++)  { 
my $mean = $sum/$size;
};
print "$mean\n";

thanks in advance.

Answer 1

OK some pointers to get you going :

You can put all the numbers into an array :

my @result = split(m/\d+/, $line);
#average 
use List::Util qw(sum);
my $sum = sum(@result);

You can then access individual columns with $result[$index] where index is the number of column you want to access.

Also note that :

$total = $line + $total;
$count = $count + 1;

Can be rewritten as :

$total += $line;
$count += 1;

Finally make sure that you are reading the file :

put a “debugging” print into the while loop :

print $line, "\n";

This should get you going 🙂