Beefy Boxes and Bandwidth Generously Provided by pair Networks
go ahead... be a heretic
 
PerlMonks  

Re: (bbfu) (another way) Re: Replacing a given character starting with the xth occurence in a string

by zeidrik (Scribe)
on May 21, 2001 at 13:55 UTC ( #81938=note: print w/ replies, xml ) Need Help??


in reply to (bbfu) (another way) Re: Replacing a given character starting with the xth occurence in a string
in thread Replacing a given character starting with the xth occurence in a string

here comes another way :)

#!/usr/local/bin/perl -w use strict; my $s = "Terence and Philip are sweet\n"; my $c = 'e'; my $r = 1; my $n = 3; sub mine { my ($str,$chr,$new,$nbr)=@_; my $reg="(.+?)$chr" x --$nbr; $_=$str; (/$reg/)&&($str=$&)&&($_=$')&&(s/$chr/$new/g); return $str.$_; } print mine($s,$c,$r,$n);
The code for benchmarking agains BBFU's proc and Quent's
#!/usr/local/bin/perl -w use strict; my $s = "Terence and Philip are sweet\n"; my $c = 'e'; my $r = 1; my $n = 3; sub mine { my ($str,$chr,$new,$nbr)=@_; my $reg="(.+?)$chr" x $nbr; $_=$str; (/$reg/)&&($str=$&)&&($_=$')&&(s/$chr/$new/g); return $str.$_; } sub bbfus { my ($str, $chr, $rep, $nth) = @_; my $pos = 0; $pos = index($str, $chr, $pos+1) for(1..$nth); substr($str, $pos) =~ s/$chr/$rep/g; return $str; } sub quents { my ($str, $chr, $rep, $nth) = @_; my $i = 1; $str =~ s/($chr)/$i++<$nth?$1:$rep/eg; return $str; } use Benchmark qw( timethese cmpthese ); cmpthese(500000, { "BBFU'S" => sub { bbfus ($s, $c, $r, $n) }, "Quent's" => sub { quents ($s, $c, $r, $n) }, "MINE" => sub { mine ($s,$c,$r,$n) }, });
AND THE BENCHMARKS :)
Benchmark: timing 500000 iterations of BBFU'S, MINE, Quent's... BBFU'S: 20 wallclock secs (19.45 usr + 0.00 sys = 19.45 CPU) @ 25 +706.94/s (n=500000) MINE: 19 wallclock secs (19.87 usr + 0.02 sys = 19.88 CPU) @ 25 +146.69/s (n=500000) Quent's: 25 wallclock secs (24.97 usr + 0.00 sys = 24.97 CPU) @ 20 +026.70/s (n=500000) Rate Quent's MINE BBFU'S Quent's 20027/s -- -20% -22% MINE 25147/s 26% -- -2% BBFU'S 25707/s 28% 2% --


Comment on Re: (bbfu) (another way) Re: Replacing a given character starting with the xth occurence in a string
Select or Download Code

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://81938]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others studying the Monastery: (9)
As of 2015-07-29 07:02 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    The top three priorities of my open tasks are (in descending order of likelihood to be worked on) ...









    Results (260 votes), past polls