Return a certain number of words of a string?

I have a long string which is actually a paragraph.

Can I have php only include the first X number of full words from the string?

Ideally, I'd like to include the number of words closest to, say, the 80-character point. How could I search for a space near that point?

I know I can *count* words, but is there a way to have a substring of X many words?

Thanks!

Example:
$paragraph = "This is my dummy paragraph that includes no important facts and in fact I am making it all up off the top of my head. I trust it was enjoyed by all."

My web site displays:
"This is my dummy paragraph that includes no important facts and"

But $paragraph changes depending on the page, so I can't just lop it off at a certain number of characters.

 

function substr_words ($paragraph, $num_words) {
  $paragraph = explode (' ', $paragraph);
  $paragraph = array_slice ($paragraph, 0, $num_words);
  return implode (' ', $paragraph);
}

PHP:

Or, maybe something like this would suit your needs better.

function cut_paragraph ($paragraph, $limit=80) {
  $pos = strrpos ($paragraph, ' ', $limit);
  if (false !== $pos) {
    return substr ($paragraph, 0, $pos);
  }
  return $paragraph;
}

PHP:

 

$paragraph = "This is my dummy paragraph that includes no important facts and in fact I am making it all up off the top of my head. I trust it was enjoyed by all.";

$rough_short_par = substr($paragraph, 0, 80); //chop it off at 80
$last_space_pos = strrpos($rough_short_par, " "); //search from end: http://uk.php.net/manual/en/function.strrpos.php
$clean_short_par = substr($rough_short_par, 0, $last_space_pos);
// add three dots...
$clean_sentence = $clean_short_par . "...(read more)"; //could link the read more to full article
echo $clean_sentence;

PHP:

 

Thanks guys!

T0PS3O, I tried yours first and it works great. Sorry I didn't get a chance to test yours, exam

What a great thing php is

 

I'm trying to implement the solution below to return a set number of words of a string but I'm a noobie and I'm not quite sure how to implement it.

Right now, the output is generated with

<?php echo cOut($row[8]); ?>

PHP:

since the data resides in row 8 of the database table. This returns all of the data but what I want is just the 1st 20 or 30 words.

Any suggestions on how to get this to work for me?