Thanks guys! Since these are membership lists, and I need to know who cancelled their membership (would be on first list, but not on second list), and who are the new members (would be on second list, but not on first). So, I would probably want something like this: 
foreach (keys %firsthash) {
  if (exists($secondhash{$_})) {
    delete($firsthash{$_};
    }
}
foreach (keys %secondhash) {
  if (exists($firsthash{$_})) {
    delete($secondhash{$_};
    }
}

[download]
The result would be that I would have cancelled members in the firsthash and new members in the second hash. Right?

In reply to Re^2: Need advice on hashes and methods by tom2112
in thread Need advice on hashes and methods by tom2112

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.