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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% --


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