Re: Exec'ing a regex stored in a scalar variable

$string =~ $regexp works if $regexp contains a regular expression. It doesn't in your case. "s/.../.../" is the Perl substitution operator, not a regular expression.

If given strings, the best way I can think of doing a substitution is:

$regexp = "a";
$subst  = "b";
$global = 1;

if ($global) {
   $string =~ s/$regexp/$subst/g;
} else {
   $string =~ s/$regexp/$subst/;
}

# (?i...) can be used in $regexp for /.../i
# (?m...) can be used in $regexp for /.../m
# (?s...) can be used in $regexp for /.../s
# (?x...) can be used in $regexp for /.../x
# /g cannot be stored in $regexp, thus the need for $global.
# /e cannot be stored in $regexp.
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Re^2: Exec'ing a regex stored in a scalar variable by Tanktalus (Canon) on Mar 11, 2005 at 22:43 UTC
Depends on your amitiousness. `$regexp = qr/a(b+)c/; $subst = 'c$1a'; my @a = $string =~ $regexp; $subst =~ s/\$(\d)/$a[$1-1]/ge; $string =~ s/$regexp/$subst/;` [download] Warning - untested. I know I've used code similar to this in the past with a limited amount of success. (i.e., it worked for me for what I needed it to work for, and this is not a cut&paste job of that code.)	[reply] [d/l]