Just to explain what chargrill does here :
# Create a lookuptable to store found items
my %hash = ();

# Iterate over the data-array (thats what grep does here), and add the
+ item to newdata, and set the found item in the lookup table. When th
+e new item is in the lookup table, don't add it again.
my @newdata = grep { ! $hash{ $_->{operation} . $_->{machine} }++ } @$
+data;

# more readable than grep (to my opinion,probably not to all others :)
+ ), but basically the same:
my %hash = ();
my @newdata;
foreach my $item (@{$data}) {
 if (! $hash{ $item->{operation} . $item->{machine} } ) {
    $hash{ $item->{operation} . $item->{machine} } = 1 ;
    push @newdata, $item;
 }
}

[download]
"We all agree on the necessity of compromise. We just can't agree on when it's necessary to compromise." - Larry Wall.

In reply to Re^3: Need help with removing duplicate hash keys from array of hashes by jbrugger
in thread Need help with removing duplicate hash keys from array of hashes 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.