perlquestion
mce
Hi,<p>
Can anyone enlighten me about the usage of the /o option in regular expressions. I have read the documentation (camel book), but this even puzzels me more.
f.e.
<code>
my @y=(1..9);
my $x=1;
foreach my $value ( @y ) {
if ( $value =~ /$x/ ) {
print "without o\n";
}
if ( $value =~ /$x/o ) {
print "with o\n";
}
++$x;
}
</code>
will print "with o" only once while "without o" 9 times.<p>
So, this means that using /o is the same as fast way precompiling the regex, like you would with [qr]//? <p>
But what is the difference then?<br>
Perl keeps the pattern compiled in memory as well with a /o as with qr? But with qr, you can access it via a variable, and make it lexical. Is that the only difference?<p>
Is this all correct?<p>
<BR>
---------------------------<BR>
Dr. Mark Ceulemans<BR>
Senior Consultant<BR>
<a href=http://www.itmasters.com>IT Masters</a>, Belgium<BR>