Beefy Boxes and Bandwidth Generously Provided by pair Networks
Welcome to the Monastery
 
PerlMonks  

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??

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

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":



  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or How to display code and escape characters are good places to start.
Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others surveying the Monastery: (7)
As of 2022-12-05 14:57 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found

    Notices?