I have a (small) dataset in a array of hashes, like this:

@AoH = ( { 'targetL' => 'foisonnement', 'origin' => 'AMG', 'count' => '1', }, { 'targetL' => 'foisonnement', 'origin' => 'IDBR', 'count' => '1', }, { 'origin' => 'IWWF', 'targetL' => 'gonfler', 'count' => '1', }, { 'origin' => 'IWWF', 'targetL' => 'due', 'count' => '1', }, { 'origin' => 'IWWF', 'targetL' => 'due', 'count' => '1', }, );

I need to 'merge' the hashes that have the same value in key 'targetL' and keep the count of how many of them have been merged, incrementing the 'count' value. Plus, the 'origin' keys of the merged hashes should be concatenated. With the above input I need to get:

@AoHfinal = ( { 'targetL' => 'foisonnement', 'origin' => 'AMG IDBR', 'count' => '2', }, { 'origin' => 'IWWF', 'targetL' => 'gonfler', 'count' => '1', }, { 'origin' => 'IWWF', 'targetL' => 'due', 'count' => '2', }, );

I am quite new to Perl. I came out with a very bulky solution with too many loops and recreation of intermediate array of hashes. But, as far I can see, this is something that should be done in a few lines of code. In which direction should I move?


In reply to Counting elements in array of cases by Anonymous Monk

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.