Re^2: RegExp to Search All Array Members?

Having just read the section in Damian's Object Oriented Perl book about the regular use of qr, this looked like a good chance to try it out. That is, with qr, you are creating a reference to a regular expression which you can store in a scalar variable. When that scalar variable is used in a regex later on, the complilation work to prepare the referenced regex doesn't have to be repeated each time through your loop, avoiding a good amount of regex overhead.

Here's the snippet again with some tweaks to your example. Note, whenever I store a reference in a scalar, I like to suffix the identifier with _Xr, where X stands for the kind of thing that's supposed to be referenced (in this case r for "regex") and the closing r indicates that the scalar is supposed to hold a reference.

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

my @names = ("John?", "Paul", "George", "Rin.go");

my $regexStr
    = "^static\\s+\\w+\\s+("
                # Thanks moritz!
    . (join "|",map quotemeta,@names)
    . ")\\W.*";
print "$regexStr\n\n";

my $regexStr_rr = qr{$regexStr}i; # or "cloister" the 'i' in $regexStr

while(<DATA>) {
    chomp;

    my ( $hit )
        = $_ =~ /$regexStr_rr/;
  
    if ($hit) {
        print "Beatle method \"$hit\" found on this line: $_\n";
    }
    else {
        print "No Beatle method found on this line: $_\n";
    }
}

__DATA__
static int lars(...);
static bool george(...);
static int thom(...);
[download]

Comment on Re^2: RegExp to Search All Array Members? Select or Download Code

Replies are listed 'Best First'.
Re^3: RegExp to Search All Array Members? by Aceflex (Initiate) on Jan 03, 2012 at 23:33 UTC
I have tried to get this working, but have been unsuccessful. I am a noob to programming and perl so patience would be appreciated. The search NEVER matches. I made sure the case is exactly the same in the doc and still no luck Here is the code #!/usr/bin/perl -w use strict; use warnings; open(FH, "Wachterpdf2txt.txt") or die "We have a problem: $!"; my @invoiceSearch = ("phone", "hunt", "dial", "tone", "static", "18d", + "system", "voice", "numbers", "voicemail", "MLX201", "programming", +"extension", "processor", "block", "mls", "programmed", "rollover", " +extension", "partner", "crosstalk", "merlin", "ringing"); my $regexStr="^static\\s+\\w+\\s+(" . (join "\|",map quotemeta,@invoice +Search) . ")\\W.*"; print "$regexStr\n\n"; my $regexStr_rr = qr{$regexStr}i; # or "cloister" the 'i' in $regexStr while(<FH>) { chomp; my ( $hit ) = $_ =~ /$regexStr_rr/; if ($hit) { print "Beatle method \"$hit\" found on this line: $_\n"; } else { print "No Beatle method found on this line: $_\n"; } } [download] What I can't seem to find anywhere is what the ^static statement means in the Regex variable. I am pulling in a text document that was converted from .pdf I have stripped out all spaces and most punctuation. The text document looks fine to me. Any help would be appreciated!	[reply] [d/l]
Re^4: RegExp to Search All Array Members? by Anonymous Monk on Aug 16, 2012 at 20:42 UTC
A bit late, but... ^ is a special character in regex that makes it find the match at the beginning of the string. So with '^static', it will find any string that begins with 'static'. So, it would match: static bool fred(...) But it wouldn't match stat bool fred(...) since static isn't at the very beginning of it, stat is.	[reply]

Here is the code