Howdy!

I posted some sample code that demonstrates that inserting a key into a hash can change the order of the keys that were present before that insertion. That shows that the keys are inherently unordered. If you us one of the modules out there to hack the inner workings of a hash to control the order of keys you get when calling keys(), it's not a plain hash anymore.

Through the magic of tie and overload and XS, you can subvert and pervert the behavior of things, but that doesn't change the fundamental data types of scalar, hash, and array. Claiming that a hash is ordered is silly, on a par with claiming that pi is actually equal to 3. Being ordered implies a level of stability. If key X comes "before" key Y now, then orderedness implies that no sequence of insertions and deletions that do not invove X or Y will change that. It turned out to be trivial to demonstrate that that condition does not hold.

yours,
Michael

In reply to Re^4: What makes an array sorted and a hash unsorted? by herveus
in thread What makes an array sorted and a hash unsorted? by ikegami

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.