Right, it means:

• "
• zero or more of anything but " (which is stored in $1)
• another "

Of course you probably want to use something like Text::Balanced instead.

I thought that if a (^) occurs as the first character of a character class, the character class is negated.

Exactly. So, /[^"]/ matches any character that isn't a double quote. /[^"]*/ matches zero or more characters that are not double quotes, and /"([^"]*)"/ matches a double quote (the starting delimiter), zero or more characters that aren't a double quote (the content), and then a double quote (the ending delimiter). The parens capture the content.

Abigail

This is an excellent time to learn about a module called YAPE::Regex::Explain. With it, you can do the following:

#!/usr/bin/perl -w

use strict;
use YAPE::Regex::Explain;

my $regex_i_dont_understand = q~"([^"]*)"~;
print YAPE::Regex::Explain->new($regex_i_dont_understand)->explain;
__DATA__
output:
(?-imsx:"([^"]*)")

matches as follows:

NODE                     EXPLANATION
----------------------------------------------------------------------
(?-imsx:                 group, but do not capture (case-sensitive)
                         (with ^ and $ matching normally) (with . not
                         matching \n) (matching whitespace and #
                         normally):
----------------------------------------------------------------------
  "                        '"'
----------------------------------------------------------------------
  (                        group and capture to \1:
----------------------------------------------------------------------
    [^"]*                    any character except: '"' (0 or more
                             times (matching the most amount
                             possible))
----------------------------------------------------------------------
  )                        end of \1
----------------------------------------------------------------------
  "                        '"'
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------
[download]

Pretty nifty, eh? Now whenever you don't understand the way a particular regular expression works, just set $regex_i_dont_understand to it and it will explain it piece by piece.

Hope this helps.

antirice    
The first rule of Perl club is - use Perl
The ith rule of Perl club is - follow rule i - 1 for i > 1

In English, I can see the string "supplied on 5.25" disk" as valid. But since I'm of a literal mind, the disk and closing quote aren't part of the string.

So I'd propose an example of what you are talking about as something like "supplied on 5.25\" disk" which is a valid Perl string...

Not that it really matters, just a slight nitpick.

The problem is that we don't always get to deal with data we create. In my current work, I deal with POS data from many sources and lots of it. So this, in a way is a real life example. Some of the data I deal with comes in a quote-delimited fashion and I often see things like this.
You are right if I were creating these data, I would likely use double quotes only to deliniate between alpha and numeric data. Of course that's only if I were limited to using a delimiter that might appear in my data.
Unfortunitly most commercially available tools for parsing will parse these data incorrectly. Like you they view it as "supplied on 5.25" and the rest just hits the bit bucket. This is where perl comes in handy to prep data that has issues like this.

Thank goodness and LW for perl!

I thought that if a (^) occurs as the first character of a character class, the character class is negated.

The regex expression [^"] is a character class, the caret meaning, as you say, negation - 'anything but what follows'. The * after that means matc zero or more of them, greedily. The parentheses capture what's matched in $1. The enclosing quotes are matched literally. The result is that everything between the first and second quote is captured.

Another way would be to use a non-greedy expression in the capture, /"(.*?)"/

After Compline,
Zaxo

Another way would be to use a non-greedy expression in the capture, /"(.*?)"/

Uhm, not quite. You'd have to use /"(.*?)"/s. Furthermore, if you would embed the regex in a larger one, "[^"*]" would never match a double quote inside the other ones, while ".*?" may.

Abigail

Hello again, everyone. been awhile :)

$_ = '"Hello \" world!" I am Roger';
($str) = /("(?:\\"|.)*?")/x;
print "$str\n";
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