K Pfeiffer wrote:
>
> Hi y'all,
Hello,
> I have a little script that lets me test some regexes. For example at the
> prompt I type in: "\b(The|the)\b". I thought it would be better if I could
> also include the slashes and then modifiers such as 'g' and 'i':
> "/\bthe\b/i" (for example).
>
> So I modified it as below:
> -----------
> my ($count, $linenumber) = 0;
> print "Enter regex (/regex/ ): ";
> chomp (my $regex = <STDIN>);
> while (<>) {
> chomp;
> $linenumber++;
> if ($regex) {
> print "\033[32mLine $linenumber:
> \033[2;37m$`\033[00m«\033[1;33m$&\033[00m\033[00m»\033[2;37m$'\033[00m\n";
> $count++
> }
> }
> print "Matches found: $count\n";
> -----------
>
> BUT it doesn't work. I get the "use of uninitialized value in concatenation
> or string..." error for each line and an empty search result «».
>
> The old code was simply "if (/$regex/)..." and that works fine. But if I
> take the slashes out and then type them in on the command line with the
> rest of the regex it fails.
$regex is just a string unless you use the // delimiters or use it in a
context that will convert it to a regular expression.
if ( $regex ) {
# is the string true in a boolean context?
if ( /$regex/ ) {
# convert the string to a regex and bind it to $_
if ( $_ =~ $regex ) {
# convert the string to a regex and bind it to $_
If you want to include options like /i you will have to use an extended
pattern like "\b(?i:the)\b" or "\b(?i)the\b".
John
--
use Perl;
program
fulfillment
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