Can you show us a code snippet? What are you trying to do the substitution on? The following works, but I think it's not what you are asking for.

#!/usr/bin/perl -w
use strict;

my %hash = (
  foo => 'bar',
  baz => 'quux'
);

my $string = 'foo and baz';
while( my($k,$v) = each %hash ) {
  $string =~ s/$k/$v/g;
}
print $string;
[download]

What I'm asking is: "what is your substitution target"? Are you trying to simply make substitutions in a string, like I did above, or are you trying to munge hash keys or something strange like that?

Cheers,
Ovid

New address of my CGI Course.
Silence is Evil (feel free to copy and distribute widely - note copyright text)

I'm trying to substitute psudo-html into html. It would convert this string: [h2]Test[/h2] [h3]Test[/h3] into <h2>Test</h2> <h3>Test</h3>. This is what the code looks like inside my program:

# Create a hash of codes for substitution
my %directSubs = (
                  qr/\[h(\d)\]/  => '<h$1>',
                  qr/\[\/h(\d)\]/=> '</h$1>'
                  );

# Substitute the codes
while(($a,$b) = each %directSubs){
   $line =~ s/$a/$b/gi;
}
[download]

One way

#! perl -slw
use strict;

my $pseudo = '[h2]Test[/h2] [h3]Test[/h3]';

# Create a hash of codes for substitution
my %directSubs = (
         qr/\[h(\d)\]/  => '"<h$1>"',
         qr/\[\/h(\d)\]/=> '"</h$1>"'
         );

# Substitute the codes
while(($a,$b) = each %directSubs){
 $pseudo =~ s/$a/$b/giee;
}

print $pseudo;

__END__
# Output
C:\test>215723
<h2>Test</h2> <h3>Test</h3>

C:\test>
[download]

---

Okay you lot, get your wings on the left, halos on the right. It's one size fits all, and "No!", you can't have a different color.
Pick up your cloud down the end and "Yes" if you get allocated a grey one they are a bit damp under foot, but someone has to get them.
Get used to the wings fast cos its an 8 hour day...unless the Govenor calls for a cyclone or hurricane, in which case 16 hour shifts are mandatory.
Just be grateful that you arrived just as the tornado season finished. Them buggers are real work.

Actually, from man perlop:


qr/STRING/imosx
   This operator quotes (and possibly compiles) its
   STRING as a regular expression.  STRING is inter­
   polated the same way as PATTERN in "m/PATTERN/".
   If "'" is used as the delimiter, no interpolation
   is done.  Returns a Perl value which may be used
   instead of the corresponding "/STRING/imosx"
   expression.

A little experiment:


use strict
my %a = (qr/(.+)pippo/, 1);
print keys %a;
[download]

prints out (?-xism:(.+)pippo), which can be used in the matching part of a regex, while

use strict;
my %a = (1,2);
my %b = (\%a, 3);
for (keys %b) { print %$_ };
[download]

dies with error
Can't use string ("HASH(0x81005ac)") as a HASH ref while "strict refs" in use at - line 5.

The stupider the astronaut, the easier it is to win the trip to Vega - A. Tucket

Ok, I'm confused. I made the corrections and it works fine now, with no errors even using the strict and warning pragmas. Shouldn't it fail to work?

qr creates a Regexp reference.

I've never heard of a regex reference? Could you give me a pointer to the docs on that?

---

Okay you lot, get your wings on the left, halos on the right. It's one size fits all, and "No!", you can't have a different color.
Pick up your cloud down the end and "Yes" if you get allocated a grey one they are a bit damp under foot, but someone has to get them.
Get used to the wings fast cos its an 8 hour day...unless the Govenor calls for a cyclone or hurricane, in which case 16 hour shifts are mandatory.
Just be grateful that you arrived just as the tornado season finished. Them buggers are real work.