For very small hashes, performing two lc(...$a...) calls per sort iteration is okay.

For larger hashes, performing all those calls per sort iteration will bog you down. As the number of items increases, the number of sorting comparison increases geometrically. If you need speed, look around for the "Schwartzian Transform" (named after our own merlyn). 

my @ordered =
   map { $_->[0] }
   sort { $a->[1] cmp $b->[1] }
   map { [ $_, expensive_function($_) ] }  # such as lc()
   @unordered;                             # such as keys %hash

[download]

This calls an expensive setup operation once per item and saves the resulting value, then sorts according to these temporary values, then strips away the temporary values, leaving the original items, but in the right order.

--
[ e d @ h a l l e y . c c ]

In reply to Re: Re: alphabetize a hash ignoring upper/lower cases by halley
in thread alphabetize a hash ignoring upper/lower cases by Evanovich

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.