unbound variables in perl regexes

I have a bunch of lines like these:

John Smith
Jane Doe
Dr. Bruce Wayne

and I would like to put the names into a csv file with two columns: title and full name. I'm using the regex for this: /(\w*\. )?(.*)/, then I print开发者_运维问答 "$1;$2". The problem is that in names without a title, perl complains about an uninitialized value $1. How do I make it just use an empty string?

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Just change your regex to :

my $re = qr/(\w*\. |)(.*)/;
 add alternation --^

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In general to make part of a match optional you use ?, on a (?: ) group if necessary. Just using ? after a capturing group will leave that capture variable undef if omitted, but you can use a non-capturing group inside the capturing group:

/((?:\w*\. )?)(.*)/;

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To address the problem in another way, Lingua-EN-NameParse might help.