Re: Speed comparison of regex versus index, lc, and / /i


Quoth "A. Sinan Unur" <1usa@xxxxxxxxxxxxxxxxxxx>:

Changing this to

while ( $text =~ /\Q$ss\E/og ) {

makes regex_find faster by about 1%.

my $rx = qr/\Q$ss/;

...

while ($text =~ /$rx/g) {

is both clearer and safer. If the program is modified so that $ss is
actually variable (say, the whole thing is made into a sub) then /o
would cause it to fail in ways that are rather hard to diagnose.

Note that m// will only use the precompiled form of the qr// if the
$rx is the only thing in the match. Something like /^$rx/ or
/$rx1|$rx2/ or even / $rx/x will cause the regex to be recompiled
every time all over again.

Ben

--
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