G'day librarat,

"My goal is to iterate through the loaded hash and remove key/value pairs from each hash within the array where key names are listed in a pre-defined array."

I'd probably tackle that like this: 

 perl -Mstrict -Mwarnings -e '
    use Data::Dumper;
    my @keeps = qw{a b};
    my %to_keep = map { $_ => 1 } @keeps;
    my $data = {
        count => 5509,
        sms => [{a => 1, b => 2, c => 3, d=>4}, {b => 2, c => 3, e => 
+5}]
    };
    print Dumper $data;
    for my $sms_ref (@{$data->{sms}}) {
        delete @$sms_ref{ grep { ! $to_keep{$_} } keys %$sms_ref };
    }
    print Dumper $data;
'
$VAR1 = {
          'count' => 5509,
          'sms' => [
                     {
                       'c' => 3,
                       'a' => 1,
                       'b' => 2,
                       'd' => 4
                     },
                     {
                       'e' => 5,
                       'c' => 3,
                       'b' => 2
                     }
                   ]
        };
$VAR1 = {
          'count' => 5509,
          'sms' => [
                     {
                       'a' => 1,
                       'b' => 2
                     },
                     {
                       'b' => 2
                     }
                   ]
        };

[download]

Update: Removed the exists from ... grep { ! exists $to_keep{$_} } .... It was redundant - see discussion below. Thanks ++LanX.

-- Ken

In reply to Re: Parsing an Array of Hashes, Modifying Key/Value Pairs by kcott
in thread Parsing an Array of Hashes, Modifying Key/Value Pairs by librarat

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.