<voice type="marvin_the_martian"<Oohh, you have made me very skeptical</voice>

So I tried a couple of benchmarks. (I'm using 5.6.1, build 626 from ActiveState.) Here's the code:

use Benchmark;

$var = '\a\\aa\\\aaa\\\\aaaa'x100;

print "s:  ";
timethis(100000, '$var =~ s/\\\//g'); # 3 \ for benchmark

print "tr: ";
timethis(100000, '$var =~ tr/\\\//d');
[download]

and here's the results

s:  timethis 100000:  1 wallclock secs ( 0.51 usr +  0.00 sys =  0.51 
+CPU) @ 195694.72/s (n=100000)
tr: timethis 100000:  2 wallclock secs ( 1.68 usr +  0.00 sys =  1.68 
+CPU) @ 59453.03/s (n=100000)
[download]

You can play with $var and see the effect on the timings. Maybe tr used to be faster, but that's no longer the case.

<soapbox>
It's really beside the point. The point is the right tool for the job. In this case the right tool is the substitution operator. If you wanted to make multiple single character changes in the string then tr is what you want. Note the difference between:

$var =~ tr /ab/cd/;
# and
$var =~ s /ab/cd/g;
[download]

</soapbox>

Have fun,
Carl Forde

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