Look at where $hwwns is defined.

As you've only pasted a bit of code out of context we really don't have much to go on here.

$hwwns->{$hwpath} = $hwwn assigns the value of $hwwn to the KEY named with the value of $hwpath

the hash ref $hwwns was "declared somewhere else"(TM) within your code that you have not shared with us

Here's a quick example to show you how hash references work:

#!/usr/bin/perl
use strict;
use warnings;

use Data::Dumper;

# Declare the hash reference with an empty hash
my $hash = {};

# assign the value "bar" to the key foo
$hash->{foo} = 'bar';

# This prints the values in the hash
# $VAR1 = {
#          'foo' => 'bar'
#         };
print Dumper $hash;

# you can retrieve the value by specifying the hash key directly also
# prints "bar"
print $hash->{foo} . "\n";

# we can use variables to assign key names:
foreach my $key (qw(abc def lmnop zaxy)) {
    my $value = reverse $key;
    $hash->{$key} = $value;
}

# since this is test data, I've just reversed the key names
# to show the differentiation between $KEY and $VALUE

# Now our hash looks something like this:
# $VAR1 = {
#          'zaxy' => 'yxaz',
#          'lmnop' => 'ponml',
#          'def' => 'fed',
#          'abc' => 'cba',
#          'foo' => 'bar'
#        };
print Dumper $hash;

[download]

If you can provide more information, like a full sub definition, we can probably provide a more definite answer.

In reply to Re^3: Arrow operator usage in perl by three18ti
in thread Arrow operator usage in perl by dvinay

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.