Beefy Boxes and Bandwidth Generously Provided by pair Networks
Pathologically Eclectic Rubbish Lister
 
PerlMonks  

comment on

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

Tell us about the larger picture. There is likely to be room for improving whatever you are doing at present, or at least for us to target solutions to whatever the bigger problem is. Most gains in performance are not obtained by micro-optimizations such as you are asking for. Some tricks that will give huge performance gains in some situations will cripple the code in other situations.

That said, you can build masks then xor the strings to give something like the fast match you are looking for where the strings to be matched are fairly long. Consider:

use strict; use warnings; my $strA = 'ATGNCNC'; my $strB = 'ATGACNN'; my $strC = 'TTGACNN'; print $strA, (match ($strA, $strB) ? ' eq' : ' ne'), " $strB\n"; print $strA, (match ($strA, $strC) ? ' eq' : ' ne'), " $strC\n"; sub match { my ($mask1, $mask2) = @_; my ($str1, $str2) = @_; $mask1 =~ tr/NATGC/0\xFF/; $mask2 =~ tr/NATGC/0\xFF/; $mask1 &= $mask2; $str1 ^= $str2; $str1 &= $mask1; return $str1 !~ /[^\x00]/; }

Prints:

ATGNCNC eq ATGACNN ATGNCNC ne TTGACNN

If you can cache the masks (say you were matching all strings against all others for example) then you get a greater gain.


True laziness is hard work

In reply to Re: simple string comparison for efficiency by GrandFather
in thread simple string comparison for efficiency by CaptainF

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 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
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others about the Monastery: (5)
As of 2021-06-20 17:08 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    What does the "s" stand for in "perls"? (Whence perls)












    Results (95 votes). Check out past polls.

    Notices?