Yep. For further curiosity, I did a count on how many substr calls there were. For the ST, of course, you have two for each element, one to get the first 8 chars and one to get the rest. So for a million-element array, that's 2M calls. But for the sort-on-substr version, I got about 37M substr calls. That'll vary some depending on how unsorted the original array is, but that's probably a good ballpark number.

That's a lot more substr calls, but I guess it's still less work than building an entire new million-element array (with each element a reference to a two-element array), as the ST requires.

It does give me a (very rough) rule of thumb, though: for the ST to be more efficient, the alternative probably needs to do the equivalent of 8-10 substr calls. So just a few core functions probably won't qualify, but a longer series of functions, or some fairly complex regexes, or certainly any sort of file or database lookups, probably will. And there's always measurement to see for sure.

Aaron B.
Available for small or large Perl jobs; see my home node.

In reply to Re^4: Date to be sorted in descending and time in ascending by aaron_baugher
in thread Date to be sorted in descending and time in ascending by karthik7887

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.