Finding the paragraphs in content

Question

I am trying to create two functions, one that catches the first paragraph of some content, and one that catches the rest, but I have hit a bit of a conundrum.

I have this in my single.php:

<div class='the_content'>
  <?php the_content(); ?>
</div>

which produces:

<div class="the_content">
   <p>The content .....</p>
   <p>The content .....</p>
   <p>The content .....</p>
</div>

each paragraph all nicely wrapped in a <p> tag. I assumed that I could simple break the explode() the content based on the string </p>, theoretically splitting the content into paragraphs, but all the content is in the first resulting array element. I investigated, and there are no <p> tags in either the HTML edit, or indeed the database entry. Both look like:

The Content .....
The Content .....
The Content .....

Note:Line breaks present, but not <p> tags.

Where does Wordpress add the <p> back in? How does it find the line breaks and how can I hook a function into that?

---

FYI

Here is the function that fails, based closely on the the_content() function:

function get_first_paragraph(){
    $content = $firstcontent = get_the_content();
    $content = str_replace(']]>', ']]>', $content);
    $content = explode('</p>',$content);

    return $content[0];
}

Answer 1

The paragraphs are done by the wpautop() function, hooked to the_content, the_excerpt() & comment_text as well as 'term_description' for taxonomies.

---

The plugin linked by @javipas does an enormous effort to just add this, but it's a good example (+1). You can (modify it a little and) take the following part out of it:

// The init function
function wpse24553_add_p_the_content()
{
    add_filter( 'the_content', 'wpse24553_p_the_content' );
    add_filter( 'the_content_feed', 'wpse24553_p_the_content' );
}
add_action( 'init', 'wpse24553_add_p_the_content' );

// The actual modification function
function wpse24553_p_the_content( $the_content )
{
    global $post;

    $content_by_p = preg_split( '/<\/p>/is', $the_content );

    $i = 0;
    // Set a var to count until the targeted <p> is met - change this to your needs
    // Set to empty '' if you want to modify every paragraph
    $targeted_p = 1;

    static $new_content = '';

    foreach ( $content_by_p as $key => $p )
    {
        $i++;
        // abort and return the modified content if we're beyond the targeted <p>
        if ( $i > $targeted_p )
            {
            $new_content .= $p;
                    continue;
            }

        // Remove empty space at the end of a paragraph, then remove original <p>-tag
        $p = rtrim( $p );
        $p = preg_replace( '/<p>/is', '', $p );

        // Wrap replacements in new <p>-tags, so it validates
        $new_content .= '<p class="paragraph-link"><a name="p-'.$key.'"></a>';
        // Prepend the graf with an anchor tag
        $new_content .= '<a ref="permalink" title="Permalink to this paragraph" href="'.get_permalink( $post->ID ).'#p-'.$key.'">#</a>;
        $new_content .= $p;
        $new_content .= '</p>';
    }

    // Return the new content
    return $new_content;
}

---

Notes:

• The function needs to be placed in your functions.php
• You need to alter the function and what gets added/removed/modified with a single paragraph by yourself (no use case in the Q).
• The function currently is not tested.

Answer 2

If I have understand you, what you want is permalinks for each paragraph? The known blogger Dave Winer wrote about this a year ago, and there's a plugin called WinerLinks that puts a '#' after each paragraph, that makes that paragraph linkable.

I hope it works for you.

Answer 3

Where does Wordpress add the <p> back in?

afaik, by applying the 'the_content' filter.

possible examples for your functions:

function get_first_paragraph() { 
    $text = apply_filters('the_content', get_the_content() );
    $paragraphs = explode('</p>', $text);
    $first_paragraph = array_shift($paragraphs).'</p>';
return $first_paragraph;
}

and:

function get_last_paragraphs() { 
    $text = apply_filters('the_content', get_the_content() );
    $paragraphs = explode('</p>', $text);
    $first_paragraph = array_shift($paragraphs).'</p>';
    $rest_paragraphs = implode('</p>', $paragraphs);
return $rest_paragraphs; 
}