BrowserUk has asked for the wisdom of the Perl Monks concerning the following question:
Given a string of bytes, I want to split the string into chunks of the same byte value, as efficiently as possible. Ie. Given 'aaabcccdeeefffggg', get 'aaa','b','ccc','d','eee','fff','ggg'. The string of bytes can contain *any* values 0 .. 255.
I thought this would be easy, but has actually proved to be quite hard. The fastest, and in fact only way I've found is shown below. Test b checks the cost of the /m modifier, but is just a placeholder for something better...
$s = join'', map{ chr( 65+rand(26) ) x rand( 100 ) } 1 .. 1000;; cmpthese -1,{ a=>q[ 1 while $s =~ m[((?=(.))\2+)]g; ], b=>q[ 1 while $s =~ m[((?=(.))\2+)]mg; ] };; Rate a b a 203/s -- -1% b 205/s 1% --
Anyone see a better, ie. more efficient way?
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