What's the internal concatenation function for creating Excerpts with Wordpress?

Question

I'm already familiar with the_excerpt() and get_the_excerpt() functions. These two functions relate specifically to some node/taxonomy/whatever (post, page, custom post type) inside of Wordpress, unless I'm mistaken.

What if I have some external text, and wanted to pass it through a concatenation function. Does anyone know the function to do that?

What I'm trying to avoid, is creating a new function or re-writing an old function to limit words inside of a string. For example,

echo some_excerpt_function($text, $amount_of_words_to_limit);

I'm assuming Wordpress has something similar to this, that's why I'm asking.

Answer 1

Use wp_trim_words( $text, $num_words, $more_text )

The first argument is the text to trim, the second is the number of words you want and the third is the truncation text which defaults to an ellipsis.

The function is located in wp-includes/formatting.php line 1920 (v3.3.1)