Select Code to Download

use Benchmark;
my $junk = 'The quick brown fox Jumped over the lazy dog';
timethese(5000000,
...
    'regex1'    => '$junk =~ tr/\s//;',
    'regex2'    => '$junk =~ s/\s//g;',
});

Benchmark: timing 5000000 iterations of regex1, regex2, split...
    regex1:  3 wallclock secs ( 4.38 usr +  0.00 sys =  4.38 CPU) @ 11
+42334.93/s (n=5000000)
    regex2:  3 wallclock secs ( 3.50 usr +  0.00 sys =  3.50 CPU) @ 14
+26940.64/s (n=5000000)
     split: 15 wallclock secs (15.07 usr +  0.00 sys = 15.07 CPU) @ 33
+1762.99/s (n=5000000)