PERL Miscellaneous - Help with my regex

Author

Help with my regex

Jason Kinkade

2004-09-30, 2:56 am

I want to match any non-whitespace character between the letters of a
word.

"te.?st" will obviously match any single character between "te" and
"st" including a space and nothing. I want that, but excluding the
space.

I tried everything, like /te(.?[^\s])st/ doesn't do it, cause I still
want "nothing".

Thanks.

Gunnar Hjalmarsson

2004-09-30, 2:56 am

Jason Kinkade wrote:
> I want to match any non-whitespace character between the letters of a
> word.
>
> "te.?st" will obviously match any single character between "te" and
> "st" including a space and nothing. I want that, but excluding the
> space.
>
> I tried everything, like /te(.?[^\s])st/ doesn't do it, cause I still
> want "nothing".

/te(\S*)st/

--
Gunnar Hjalmarsson
Email: http://www.gunnar.cc/cgi-bin/contact.pl

Gunnar Hjalmarsson

2004-09-30, 2:56 am

Gunnar Hjalmarsson wrote:
>
> /te(\S*)st/

Or rather

/te(\S*?)st/

I suppose. But it depends of course on what exactly the purpose of the
regex is, and I leave it to you to figure out the difference.

Have you studied

perldoc perlrequick
perldoc perlretut
perldoc perlre

??

--
Gunnar Hjalmarsson
Email: http://www.gunnar.cc/cgi-bin/contact.pl

Jeff 'japhy' Pinyan

2004-09-30, 2:56 am

On 29 Sep 2004, Jason Kinkade wrote:

>I want to match any non-whitespace character between the letters of a
>word.
>
>"te.?st" will obviously match any single character between "te" and
>"st" including a space and nothing. I want that, but excluding the
>space.
>
>I tried everything, like /te(.?[^\s])st/ doesn't do it, cause I still
>want "nothing".

You mean you want to match "test" or "teXst", where X is a non-whitespace
character?

/te\S?st/

--
Jeff "japhy" Pinyan % How can we ever be the sold short or
RPI Acacia Brother #734 % the cheated, we who for every service
Senior Dean, Fall 2004 % have long ago been overpaid?
RPI Corporation Secretary %
http://japhy.perlmonk.org/ % -- Meister Eckhart

Shawn Corey

2004-09-30, 11:35 am

Gunnar Hjalmarsson wrote:
> Or rather
>
> /te(\S*?)st/
>
> I suppose. But it depends of course on what exactly the purpose of the
> regex is, and I leave it to you to figure out the difference.

Mileage may vary.
--- Shawn

#!/usr/bin/perl

use strict;
use warnings;

use Benchmark;

my @tests = (
"test",
"te st",
"teXst",
"te st",
"teXXXXXXXXXst",
"te\xA0st",
"te\tst",
'te' . ( ' ' x 1_000 ) . 'st',
'te' . ( 'X' x 1_000 ) . 'st',
);

for my $s ( @tests ){
print "Testing $s\n";
timethese( 1_000_000, {
'greedy \S* ' => sub { $s =~ /te(\S*)st/; },
'frugal \S*?' => sub { $s =~ /te(\S*?)st/; },
});
print "\n";
}

__END__

Testing test
Benchmark: timing 1000000 iterations of frugal \S*?, greedy \S* ...
frugal \S*?: 3 wallclock secs ( 2.92 usr + 0.00 sys = 2.92 CPU) @
342465.75/s (n=1000000)
greedy \S* : 3 wallclock secs ( 3.27 usr + 0.00 sys = 3.27 CPU) @
305810.40/s (n=1000000)

Testing te st
Benchmark: timing 1000000 iterations of frugal \S*?, greedy \S* ...
frugal \S*?: 2 wallclock secs ( 1.76 usr + 0.00 sys = 1.76 CPU) @
568181.82/s (n=1000000)
greedy \S* : 2 wallclock secs ( 1.75 usr + 0.00 sys = 1.75 CPU) @
571428.57/s (n=1000000)

Testing teXst
Benchmark: timing 1000000 iterations of frugal \S*?, greedy \S* ...
frugal \S*?: 3 wallclock secs ( 3.09 usr + 0.00 sys = 3.09 CPU) @
323624.60/s (n=1000000)
greedy \S* : 3 wallclock secs ( 3.21 usr + 0.00 sys = 3.21 CPU) @
311526.48/s (n=1000000)

Testing te st
Benchmark: timing 1000000 iterations of frugal \S*?, greedy \S* ...
frugal \S*?: 2 wallclock secs ( 1.89 usr + 0.00 sys = 1.89 CPU) @
529100.53/s (n=1000000)
greedy \S* : 2 wallclock secs ( 1.84 usr + 0.00 sys = 1.84 CPU) @
543478.26/s (n=1000000)

Testing teXXXXXXXXXst
Benchmark: timing 1000000 iterations of frugal \S*?, greedy \S* ...
frugal \S*?: 4 wallclock secs ( 3.35 usr + 0.00 sys = 3.35 CPU) @
298507.46/s (n=1000000)
greedy \S* : 3 wallclock secs ( 3.39 usr + 0.00 sys = 3.39 CPU) @
294985.25/s (n=1000000)

Testing te�st
Benchmark: timing 1000000 iterations of frugal \S*?, greedy \S* ...
frugal \S*?: 3 wallclock secs ( 3.19 usr + 0.00 sys = 3.19 CPU) @
313479.62/s (n=1000000)
greedy \S* : 4 wallclock secs ( 3.21 usr + 0.00 sys = 3.21 CPU) @
311526.48/s (n=1000000)

Testing te st
Benchmark: timing 1000000 iterations of frugal \S*?, greedy \S* ...
frugal \S*?: 1 wallclock secs ( 1.73 usr + 0.00 sys = 1.73 CPU) @
578034.68/s (n=1000000)
greedy \S* : 2 wallclock secs ( 1.75 usr + 0.00 sys = 1.75 CPU) @
571428.57/s (n=1000000)

Testing te

st
Benchmark: timing 1000000 iterations of frugal \S*?, greedy \S* ...
frugal \S*?: 19 wallclock secs (18.35 usr + 0.00 sys = 18.35 CPU) @
54495.91/s (n=1000000)
greedy \S* : 5 wallclock secs ( 5.87 usr + 0.00 sys = 5.87 CPU) @
170357.75/s (n=1000000)

Testing
teXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXst
Benchmark: timing 1000000 iterations of frugal \S*?, greedy \S* ...
frugal \S*?: 32 wallclock secs (31.42 usr + 0.00 sys = 31.42 CPU) @
31826.86/s (n=1000000)
greedy \S* : 19 wallclock secs (18.75 usr + 0.00 sys = 18.75 CPU) @
53333.33/s (n=1000000)

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