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

I am trying to do a pattern match and having issues.

The Main string: this is my teststring. LoadStore.SGE.\sr1_addr_reg_tmp_reg[0]

Regexp: LoadStore\.SGE\.\\.r._addr_reg_tmp_reg

I am positive the regexp is correct but it still doesnt match.

Also, I am getting an 'Unrecognized escape \s passed through' when I am passing my main string to a variable. The \s is not a space but a literal \s

Appreciate the help.

Replies are listed 'Best First'.
Re: Regex question
by tangent (Parson) on Jun 24, 2016 at 00:07 UTC
    When you have an escape character ('\') in your string the way you assign it to a variable will affect the result. If you assign using double quotes then you need to escape the escape character in your string, just like you do in the regular expression, and this is what the error is telling you. If you use single quotes it will work without escaping: 
    my $string;

print "Double quotes\n";
$string = "LoadStore.SGE.\sr1_addr_reg_tmp_reg[0]";
match();

print "Double quotes with escape\n";
$string = "LoadStore.SGE.\\sr1_addr_reg_tmp_reg[0]";
match();

print "Single quotes\n";
$string = 'LoadStore.SGE.\sr1_addr_reg_tmp_reg[0]';
match();

sub match {
    if ( $string =~ m/LoadStore\.SGE\.\\.r._addr_reg_tmp_reg/ ) {
        print "match\n";
    }
    else {
        print "no match\n";
    }
}

    [download]
    Output 
    Double quotes
no match
Error: Unrecognized escape \s passed through

Double quotes with escape
match

Single quotes
match

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