Regular expression for length only - any characters

I'm try开发者_StackOverflow中文版ing to regex the contents of a textarea to be between 4 and 138 characters.

My regular expression is this: '/^.{4,138}$/'

But - I want the user to be able to include return characters, which I believe the "." keeps them from doing. Thoughts on what I need to change?

EDIT :

Obviously there are other ways to get the length of text - strlen...etc, but I'm looking for regex specifically due to the nature of the check (ie a plugin that requires regex)

I want the user to be able to include return characters, which I believe the "." keeps them from doing. Thoughts on what I need to change?

Either:

• change the . to [\s\S] (whitespace/newlines are part of \s, all the rest is part of \S)
• use the SINGLE_LINE (a.k.a DOTALL) regex flag /…/s

Why don't you just check the string length using strlen? It would be much more efficient than doing a regex. Plus, you can give meaningful error messages.

$length = strlen($input);

if ($length > 138)
   print 'string too long';
else if ($length < 4)
   print 'string too short';

Either

/^.{4,138}$/s

or

/^[\s\S]{4,138}$/ 

will match newlines.

The s flag tells the engine to treat the whole thing as a single line, so . will match \n in addition to what it usually matches. Note that this also causes ^ and $ to match at the beginning and end of the entire string (rather than just the beginning/end of each line) unless you also use the m flag.

Here's some more info on regex flags.

Try '/^.{%d,%d}$/s' to have . match newlines as well.