Excerpts that don't truncate words

Question

I know I can control the length of excerpts using a filter, however it sets the length globally. In my case I have different lengths of excerpts on three different pages.

This is what I have now. I'd like to improve it so it doesn't truncate words.

$content_to_excerpt = strip_tags( strip_shortcodes( get_the_content() ) );
$pos = strpos($content_to_excerpt, ' ', 160);
if ($pos !== false) {
 echo  "<p>" . substr($content_to_excerpt, 0, $pos) . "...</p>";
}

Answer 1

Set the filter dynamically based on the page you are loading. If category archive pages have a 100 word excerpt, but posts have a 10 word excerpt, and everything else uses the default:

function my_custom_excerpt_length( $orig ) {
    if( is_category() ) {
        return 100;
    } elseif( is_single() ) {
        return 10;
    }

    return $orig;
}
add_filter( 'excerpt_length', 'my_custom_excerpt_length' );

You can get even more specific, giving specific categories a different length.

---

In response to Rarst, a new template function the_excerpt_length() for outputting the excerpt with a specific number of words:

// Excerpt with a specific number of words, i.e. the_excerpt( 100 );
function the_excerpt_length( $words = null ) { 
    global $_the_excerpt_length_filter;

    if( isset($words) ) { 
        $_the_excerpt_length_filter = $words;
    }   

    add_filter( 'excerpt_length', '_the_excerpt_length_filter' );
    the_excerpt();
    remove_filter( 'excerpt_length', '_the_excerpt_length_filter' );

    // reset the global
    $_the_excerpt_length_filter = null;
}

function _the_excerpt_length_filter( $default ) { 
    global $_the_excerpt_length_filter;

    if( isset($_the_excerpt_length_filter) ) { 
        return $_the_excerpt_length_filter;
    }   

    return $default;
}

This would be used in your template file, i.e.:

<div class="entry">
    <?php the_excerpt_length( 25 ); ?>
</div>

Answer 2

I know I've seen this question on StackOverflow before. Not specific to WordPress excerpt, but on truncating strings on PHP without truncate words. Looking back on StackOverflow itself, I found this link pretty helpful on this subject.

The code being used there is:

// Original PHP code by Chirp Internet: www.chirp.com.au
// Please acknowledge use of this code by including this header. 
function myTruncate($string, $limit, $break=".", $pad="...") { 
  // return with no change if string is shorter than $limit
  if(strlen($string) <= $limit) return $string;

  // is $break present between $limit and the end of the string?
  if(false !== ($breakpoint = strpos($string, $break, $limit))) {
    if($breakpoint < strlen($string) - 1) {
      $string = substr($string, 0, $breakpoint) . $pad; 
    } 
  } 
  return $string; 
}

Hope this helps!