Re^4: Faster regex to split a string into runs of similar characters?

/((.)\2*)/g does though,

Huh:) How did I missed that?!

... faster (by 12% on my computer).

Only 4% difference on mine under 5.10 or 5.22:

## this 5.10
[0]{} Perl> cmpthese -1,{a=>q[ 1 while $s =~ m[((?=(.))\2+)]sg;],b=>q[
+1 while $s =~ m[((.)\2*)]sg;] };;
   Rate   a   b
a 204/s  -- -4%
b 212/s  4%  --
[0]{} Perl> cmpthese -1,{a=>q[ 1 while $s =~ m[((?=(.))\2+)]sg;],b=>q[
+1 while $s =~ m[((.)\2*)]sg;] };;
   Rate   a   b
a 204/s  -- -4%
b 212/s  4%  --
[0]{} Perl>

C:\test>\Perl22\bin\perl.exe \Perl22\bin\p1.pl
[0]{} Perl> $s = join'', map{ chr( 65+rand(26) ) x rand( 100 ) } 1 .. 
+1000;;
[0]{} Perl> cmpthese -1,{a=>q[ 1 while $s =~ m[((?=(.))\2+)]sg;],b=>q[
+1 while $s =~ m[((.)\2*)]sg;] };;
   Rate   a   b
a 229/s  -- -3%
b 235/s  3%  --
[0]{} Perl> cmpthese -1,{a=>q[ 1 while $s =~ m[((?=(.))\2+)]sg;],b=>q[
+1 while $s =~ m[((.)\2*)]sg;] };;
   Rate   a   b
a 229/s  -- -4%
b 238/s  4%  --
[download]

A small, but consistent gain. Thanks.

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