Hello bsherkhane,

As Anonymous Monk says, if this is a database question, then hashes aren’t needed.

However, if you do have two hashes and want to find their intersection, just remember that the keys of a hash are accessible as a list via the Perl built-in keys function. So you really want the intersection of two lists, and this is an FAQ: see perlfaq4#How-do-I-compute-the-difference-of-two-arrays?-How-do-I-compute-the-intersection-of-two-arrays?

Update: The logic is actually simpler with hashes: because each key can occur only once in a given hash, you only need to determine whether an entry corresponding to each key in the first hash exists in the second:

use strict;
use warnings;
use Data::Dump;

my %hash1 = ( a => 1, b => 2, c => 3, );
my %hash2 = ( b => 4, e => 5, f => 6, c => 7, );
my %intersection;

for my $key (keys %hash1)
{
    $intersection{$key} = [ $hash1{$key}, $hash2{$key} ]
        if exists $hash2{$key};
}

dd \%intersection;

[download]

Output:

18:00 >perl 1527_SoPW.pl
{ b => [2, 4], c => [3, 7] }

18:01 >

[download]

(Of course, you’ll have to decide what to do when the values differ. I’ve just included both values in an anonymous array.)

Hope that helps,

Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

In reply to Re: intersecting two hashes by Athanasius
in thread intersecting two hashes by bsherkhane

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.