Ch. 15 in Learning Perl also gives a good explaination of transliteration.

You are new to Perl. You will probably save yourself a ton of time if you start all of your scripts by turning on warnings and using strict. For example:

#!/usr/bin/perl -w
use strict;
[download]

Try these on the above script and you might get a clue that in Perl strings are not arrays. (:

Definitely start using the '-w' and 'strict' as recommended by others. This will put you into a better development path earlier.

And, forget just about everything you think you know about string manipulation. When it comes to string manipulation Perl is light-years ahead of anything else I've looked at. You will be much better off just forgetting the way you've done it before and look around at the amazing functions available in Perl.

There are many excellent books. You'll see them in the "Reviews" node at the top of this page. I suppose my current favorite must book is "Programming Perl" by Larry Wall, Tom Christiansen and Jon Orwant. You'll see folks around here talking about "The Camel" or "Camel". This is that book. (It has a camel on the front cover.)

Good lucking. You're going to fall in love with Perl.

Claude

$instring = "This-is-my-string";
$outstring = $instring;
$outstring =~ s/-/_/g;
print $outstring;
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-- tune

I You are looking to just replace a specific char with a different char then tr works and is more effcient This node shows a benchmark comparision of the two methods.

UPDATE: As Xxaxx points out below my benchmark was bit off. I re-ran it using the actuall functions needed for this problem and got these results

Benchmark: timing 500000 iterations of Method One TR, Method Two s...
Method One TR:  2 wallclock secs ( 1.87 usr +  0.00 sys =  1.87 CPU) @
+ 267379.68/s (n=500000)
Method Two s:  5 wallclock secs ( 4.84 usr +  0.00 sys =  4.84 CPU) @ 
+103305.79/s (n=500000)
[download]


For more details click these nodes and see the discussion.

I recommend running the benchmark again using the actual functions.

In your referenced benchmark you're comparing:

$data =~ tr/a-z/A-Z/;
and
$data =~ s/(A-Za-z+)/uc($1)/ge;

The uc($1) is a little different than:
$outstring =~ s/-/_/g;

When I ran the actual benchmark I got the following results:

Run 1: (n=5000000)
Method One TR: 3 wallclock secs ( 3.00 usr + 0.00 sys = 3.00 CPU) @ 166666.67
Method Two S: 3 wallclock secs ( 3.05 usr + 0.00 sys = 3.05 CPU) @ 163934.43

Run 2: (n=5000000)
Method One TR: 2 wallclock secs ( 2.96 usr + 0.00 sys = 2.96 CPU) @ 168918.92
Method Two S: 3 wallclock secs ( 3.08 usr + 0.00 sys = 3.08 CPU) @ 162337.66

Run 3: (n=5000000)
Method One TR: 4 wallclock secs ( 2.97 usr + 0.00 sys = 2.97 CPU) @ 168350.17
Method Two S: 3 wallclock secs ( 3.08 usr + 0.00 sys = 3.08 CPU) @ 162337.66

Seems like they are pretty much equal. But, alas, I'm real new to this benchmark stuff and I could have some weird caching issue.

Even so without the eval of uc($1) this is certainly no 17 to 1 ratio as the referenced benchmark shows.

Hope this helps
Claude
p.s. Thanks to Desdinova for introducing me to the world of benchmarks.