The array needs to be reset. This is because subsequently the array needs to be populated with other items; the next hash will be an array of these other items. It the array is not reset, items from the previous operation will be appended to the items in the current operation....

No. It doesn't. Use a different array.

You've stored a reference to @this_array in the hash; if you modify it, then you are modifying (deleting) the data that reference points to.

You might just as well not have stored it in the first place, if as soon as you do, you destroy the data the reference points to.

Update:Maybe this will clarify things?:

@this_array = 0..9;;

$hash{ akey } = \@this_array;;

pp \%hash;;
{ akey => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] }

@this_array =  ();;

pp \%hash;;
{ akey => [] }

[download]
With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

In reply to Re^5: Help !!! Symbolic Math Factroize Subroutine is clobbering my hash by BrowserUk
in thread Help !!! Symbolic Math Factroize Subroutine is clobbering my hash by ipreferperl

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.