Please forgive me, I am a novice at best.

No worries.

it doesn't seem to work on my data.

The problem here is that you haven't shown what your data is and you haven't shown in what way it "doesn't seem to work". This gives the people who want to help you very little to go on. An SSCCE would be ideal.

That said, if you are using an AoA as @rows then you will have trouble. Maybe all you need is:

@rows = do { my %seen; grep { !$seen{$_->[2]}++ } @rows };

[download]

But without any data to test on, who can say?

As for explaining the code, you are grepping an array for entries which don't match entries in a hash which you build up as you go along. This is the standard, simplest de-duplication technique (without resorting to modules) as outlined in the FAQ How can I remove duplicate elements from a list or array?.

In reply to Re: Removing duplicates in multi-dimensional arrays by hippo
in thread Removing duplicates in multi-dimensional arrays by DamnitAddie

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.