RegExp in JavaScript, when a quantifier is part of the pattern

Question

I have been trying to use a regexp that matches any text that is between a caret, less than and a greater than, caret.

So it would look like: ^< THE TEXT I WANT SELECTED >^

I have tried something like this, but it isn't working: ^<(.*?)>^

I'm assuming this is possible, right? I think the reason I have been having such a tough time is because the caret serves as a quantifier. Thanks for any help I get!

Update

Just so everyone knows, they following from am not i am worked

 /\^<(.*?)>\^/

But, it turned out that I was getting html entities since I was getting my string by using the .innerHTML property. In other words,

> ... &gt;
< ... &lt;

To solve this, my regexp actually looks like this:

\^&lt;(.*?)((.|\n)*)&gt;\^

This includes the fact that the string in between should be any character or new line. Thanks!

Caret not carrot :)

Ben Swinburne
– Ben Swinburne

2012-07-30 20:26:37 +00:00
Commented Jul 30, 2012 at 20:26 — Ben Swinburne
– Ben Swinburne, Commented Jul 30, 2012 at 20:26
Thank you! I knew that couldn't be right!

frshca
– frshca

2012-07-30 21:08:30 +00:00
Commented Jul 30, 2012 at 21:08 — frshca
– frshca, Commented Jul 30, 2012 at 21:08

user1106925 · Accepted Answer · 2012-07-30 20:23:50Z

4

You need to escape the ^ symbol since it has special meaning in a JavaScript regex.

 /\^<(.*?)>\^/

In a JavaScript regex, the ^ means beginning of the string, unless the m modifier was used, in which case it means beginning of the line.

answered Jul 30, 2012 at 20:23

user1106925

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Comments

Nicolas Stamm · Accepted Answer · 2012-07-30 21:50:29Z

0

This should work:

\^<(.*?)>\^

In a regex, if you want to use a character that has a special meaning (caret, brackets, pipe, ...), you have to escape it using a backslash. For example, (\w\b)*\w\. will select a sequence of words terminated by a dot.

Careful!

If you have to pass the regex pattern as a string, i.e. there's no regex literal like in javascript or perl, you may have to use a double backslash, which the programming language will escape to a single one, which will then be processed by the regex engine.
Same regex in multiple languages:

Python:
  import re
  myRegex=re.compile(r"\^<(.*?)>\^") # The r before the string prevents backslash escaping
PHP:
  $result=preg_match("/\\^<(.*?)>\\^/",$subject); // Notice the double backslashes here?
JavaScript:
  var myRegex=/\^<(.*?)>\^/,
      subject="^<blah example>^";
  subject.match(myRegex);

If you tell us what programming language you're writing in, we'll be able to give you some finished code to work with.

Edit: Whoops, didn't even notice this was tagged as javascript. Then, you don't have to worry about double backslash at all.

Edit 2: \b represent a word boundary. Though I agree yours is what I would have used myself.

edited Jul 30, 2012 at 21:50

answered Jul 30, 2012 at 20:24

Nicolas Stamm

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1 Comment

Alan Moore Over a year ago

A sequence of words terminated by a dot? I think you meant (\w+\s+)*\w+\.

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