Just to expand a little on the helpful info you've already gotten from davorg and ikegami, ref and Scalar::Util's reftype will both tell you (1) whether what you have is a reference, and (2) what kind of reference it is. The difference between them is what they do with a reference that's been blessed into a class. In that case, ref will give you the class name, and reftype will tell you the type of the unblessed reference.

Here's an example: 

use Scalar::Util qw( reftype );

my $blessed = bless {}, 'My::Class';
my $hashref = {};

printf "blessed is ref %s\n", ref $blessed;
printf "blessed is reftype %s\n", reftype $blessed;

printf "hashref is ref %s\n", ref $hashref;
printf "hashref is reftype %s\n", reftype $hashref;

[download]

This prints: 

blessed is ref My::Class
blessed is reftype HASH
hashref is ref HASH
hashref is reftype HASH

[download]

Both of them will return undef if you hand them something that is not a reference. Otherwise what's returned is just a regular string that you can compare with eq or pattern matches.

In reply to Re: Check whether a variable is a hash or not by kyle
in thread Check whether a variable is a hash or not by lethao

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.