Daniel Gardner wrote:
>
> >>
> >> Why slow it down with the 'i'?
> >> $searchstring=~/[a-zA-Z0-9]/;
>
> > Why slow it down with a regular expression? :-)
>
> > if ( $searchstring =~ tr/a-zA-Z0-9// ) {
>
> i was bored, and thought i'd try a little benchmark. note, this
> is for the specific problem expressed here, not the general case.
>
> i benchmarked the following:
>
> RegexWithI: $string =~ /[A-Z0-9]/i;
> RegexNoI: $string =~ /A-Za-z0-9/;
> tr: $string =~ tr/[A-Za-z0-9//;
>
> [snip benchmark results]
>
> #!/usr/bin/perl -w
>
> [snip code]
>
> sub with_i {
> my ($string) = @_;
> $string =~ /[A-Z0-9]/i;
> }
> sub without_i {
> my ($string) = @_;
> $string =~ /[A-Za-z0-9]/;
> }
> sub tr_without {
> my ($string) = @_;
> $string =~ tr/[A-Za-z0-9]//;
> }
Note that the tr/// is looking for the characters '[', 'A-Z', 'a-z',
'0-9', and ']' while the m// is not looking for the '[' and ']'
characters so they are not equivalent.
John
--
use Perl;
program
fulfillment
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