zemane has asked for the wisdom of the Perl Monks concerning the following question:

Hi,

I'm trying to match a regular expression that may contain a special char that I want it to be ignored. For example, suppose I am looking for the pattern 'aabb' and anywhere in the string I could have the special char \xFF.

So my string could be any of these:

$str = "a\xFFabb";
$str = "aa\xFFbb";
$str = "aabb\xFF";

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And I want the following code to match successfully:

if ($str =~ "aabb") {
  print "match found\n";
}
else {
  print "no match\n";
}

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Is there any way to tell Perl to ignore a certain special character when looking for a match?

I don't want to remove the special char from the string because later on I want to find this special char and use its position to insert other stuff into the string. So, this special char is used as a marker for future insertions.

Replies are listed 'Best First'.
Re: Can I make Perl ignore a special char when matching?
by GrandFather (Saint) on Jul 23, 2008 at 22:49 UTC

    Why not create a copy of the string with the special char removed and use that for the initial matching?

    Alternatively you could:

    use strict;
use warnings;

my $matchStr = 'aabb';
my $match = "\xff?" . join ("\xff?", split '', $matchStr) . "\xff?";
my $str = "aa\xffbb";

if ($str =~ $match) {
    print "Matched";
} else {
    print "No match";
}

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    Perl is environmentally friendly - it saves trees
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[d/l]
Re: Can I make Perl ignore a special char when matching?
by aquarium (Curate) on Jul 24, 2008 at 01:31 UTC
    putting things of different semantic/logical nature into one place--especially with extensibility in mind--is bound to cause problems sooner or later. better to have a separate variable or other structure attached to the string, which will contain any special things like special placemarkers. Then you have a clean string variable to match against.
    the hardest line to type correctly is: stty erase ^H
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Re: Can I make Perl ignore a special char when matching?
by jethro (Monsignor) on Jul 23, 2008 at 22:55 UTC
    Just copy $str to another variable, remove the special char from that copy before you try to match it.
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