Luke Bakken wrote:
>
> From: Larry Sandwick [mailto:[EMAIL PROTECTED]
> >
> > I have a scripted I wrote that uses *substr* on a file that has fixed
> > fields. I have to parse the file before I upload into MYSQL.
> >
> > Is there a more efficient way other than *substr*, I looked a
> > *pack* and
> > *unpack* . it did not make any sense to me.
>
> From my own limited performance testing (using the Benchmark module),
> I've found that substr is faster than unpack.
Thanks for that Luke. It seems you're right:
use Benchmark;
my $the_line = ' 304 THE CASTLE TWO DRAWER CHEST 6-168 02/18/04';
timethese(1E7, {
'unpack' => sub {
my ($item, $ldesc, $page, $d) = unpack 'A10xA28xA6xA8', $the_line;
},
'substr' => sub {
my $item = substr($the_line, 0, 10);
my $ldesc = substr($the_line, 11, 28);
my $page = substr($the_line, 40, 6);
my $d = substr($the_line, 47, 8);
},
});
**OUTPUT
Benchmark: timing 10000000 iterations of substr, unpack...
substr: 19 wallclock secs (18.19 usr + 0.00 sys = 18.19 CPU) @ 549752.61/s
(n=10000000)
unpack: 31 wallclock secs (30.64 usr + 0.00 sys = 30.64 CPU) @ 326370.76/s
(n=10000000)
I think that will surpirise quite a few people.
Rob
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