Single quotes do not interpolate, so your hash does not contain what you think it does. Add this to the top of your code:

use strict;
use warnings;
use Data::Dumper;
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print Dumper \%ipkey;
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That said, there are likely much easier ways to do what you are trying to accomplish. If you are interested, post some example data and explain what you are trying to do. Monks love that kind of thing.

Psst... just for fun, try this:

%ipkey = @rawdata;
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First off THANK YOU all for the replies.

Here is some example data that a user would put into a web page which will be passed to this perl script.

66.249.90.104 www.google.com

74.52.141.211 www.focusfaction.com

209.197.123.153 www.perlmonks.com

I am writing this code to do some checks on DNS records before we (I work on a DNS team) add the records. I wanted to place the IP address from the input into a hash key and make the value the fqdn. This way I can dig against the IP and then see if what is returned matches whats in the hash. This would tell us that the record exists and matches what we expected and no action is needed. This is just one part of a larger DNS validation script I am writing (or attempting to write).

Thanks in advance for all your help

Note that for general DNS applications, a hash is not necessarily the best choice of data structure, because one domain might resolve to different IP addresses (209.197.123.153 , 66.39.54.27 for PerlMonks) and multiple domains might resolve to the same IP address(es) (perlmonks.org , perlmonks.net and perlmonks.com use these two IP addresses). But for well-known, "major" IP addresses, a simple hash lookup might be what's needed.

$key = 'something';
print '$key', "\n";
print "$key", "\n";
print $key, "\n";
__END__
$key
something
something
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Aside from the interpolation issue already mentioned by previous answers, this is a useless use of quotes. You want to use the values of the variables, not their names, and you aren't trying to insert them into a larger string, so don't quote them at all:

$ipkey{$key} = $value;

Newbies often overthink the problem and use too much code. As code gets more complex, there is a greater chance of bugs, and it becomes less readable and harder to maintain. Here's a more concise version with notes for your education.

# always use strict & warnings
# they give useful debugging info
use strict;
use warnings;

# get your rawdata 
my @rawdata = ...

# chomp the whole array at once
chomp @rawdata;

# declare the hash
my %ipkey;

# a 'C' style for loop is useful here
# this one loops over every second array index
for (my $i = 0; $i < @rawdata; $i += 2){

    # get each pair of consecutive items from array
    my $key   = $rawdata[$_];
    my $value = $rawdata [$_ + 1];

    # then build the hash
    $ipkey{$key} = $value;    

    # and print your results
    print "Key: $key <br>Value: $value<br><br>";

    # if printing to the console, do this instead
    print "Key: $key \nValue: $value\n\n";
}
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Update:

Also note that arrays can be directly assigned to hashes.

# direct assignment
my %ipkey = @rawdata;

# iterate over hash keys & print
for (keys %ipkey) {
    print " Key: $_ \n Value: $ipkey{$_} \n\n";
}
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This works.


#!/usr/bin/perl -w
use strict;

my (%ipkey,$value,$key);
my $count = 0;
my @rawdata = ('key1','value1','key2','value2','key3','value3');

foreach (@rawdata) {
        if ($count == 0) {
                $key = $_;
                $count++;
                next;
        }else{
                $value = $_;
                $ipkey{$key} = $value;
                $count = 0;
        }
}<\code>

<br> OUTPUT<code>
  DB<4> x %ipkey
0  'key2'
1  'value2'
2  'key1'
3  'value1'
4  'key3'
5  'value3'
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