Extract certain section of posts as an excerpt in WordPress - wordpress

Question

I have a WordPress website, in which I have created multiple posts and bound them to a certain category.
Each posts has 6 paragraphs.
Here is what I am trying to achieve:
I have created a child wordpress theme file, in which I am retrieving all the posts from a particular category.
I want to display the 3rd paragraph from each posts ( upto 40 words ) as an excerpt.
Anyone can help me to achieve this?
Any help will be appreciated...
Thank You
Edited:
Contents of one of the posts:
<div id="grey">
<div id="title">
<h1 id="divtest">Title</h1>
</div>
<div id="divContentText1"><span class="button5_hover"></span><strong>Back To Test Page</strong></div>
</div>
<div class="wrap" id="divPgInfo">
<div id="divInnerImgSliderWrap">[meteor_slideshow slideshow="test"]</div>
<div id="divImgTxtWrap">
<h4 class="innerSlideHd">Test Title</h4>
<p class="innerSlideText">It is a long established fact that a reader will be distracted by the readable content of a page when looking at its layout. The point of using Lorem Ipsum is that it has a more-or-less normal distribution of letters, as opposed to using 'Content here, content here', making it look like readable English.</p>
<p class="innerSlideText">Many desktop publishing packages and web page editors now use Lorem Ipsum as their default model text, and a search for 'lorem ipsum' will uncover many web sites still in their infancy. Various versions have evolved over the years, sometimes by accident, sometimes on purpose (injected humour and the like).</p>
<p class="innerSlideText">Many desktop publishing packages and web page editors now use Lorem Ipsum as their default model text, and a search for 'lorem ipsum' will uncover many web sites still in their infancy. Various versions have evolved over the years, sometimes by accident, sometimes on purpose (injected humour and the like).</p>
<p class="innerSlideText">Many desktop publishing packages and web page editors now use Lorem Ipsum as their default model text, and a search for 'lorem ipsum' will uncover many web sites still in their infancy. Various versions have evolved over the years, sometimes by accident, sometimes on purpose (injected humour and the like).</p>
<p class="innerSlideText">Many desktop publishing packages and web page editors now use Lorem Ipsum as their default model text, and a search for 'lorem ipsum' will uncover many web sites still in their infancy. Various versions have evolved over the years, sometimes by accident, sometimes on purpose (injected humour and the like).</p>
</div>
<div class="divClr"></div>
</div>
<div class="divClr"></div>
Now I want to show the contents from the sentence "It is a long established...."
Any help will be appreciated....
Really Thank you...

Answer 1

In You Post Editor screen at wordpress backed
Write your 3rd paragraph in "excerpt" text area. (Enable it from top of edit screen page)
For display this content in fronend use the_excerpt function.

Answer 2

Inspired by this question and by the fact that Wordpress' excerpt is often not flexible enough for user needs, I jotted down a function allowing to use any HTML tag inside the post content as this arbitrary post excerpt.
Mind that the function can get some work to improve flexibility, for example you could substitute the excerpt with this custom excerpt altogether, or perhaps implement some other parameter to allow a more in-depth searching (something like marking the excerpt paragraph with an id="excerpt").
I went for a specific solution to your problem, however, and elaborated a bit more to allow some flexibility. You can put this code in your functions.php:
/*
* Defines an arbitrary excerpt by using any post content HTML element
*
* The function accepts an optional array of arguments.
* Optional $args contents:
*
* * id - The id of the post we want the excerpt of. Defaults to the current post.
* * tag - The HTML tag we want to use as an excerpt.
* * idx - The index of that tag as calculated considering the post_content as the root.
*
* #param array|string $args See above description.
*/
function my_get_the_excerpt($args = array()) {
$defaults = array(
'id' => null,
'tag' => 'p',
'idx' => 0
);
$args = wp_parse_args($args, $defaults);
$args = (object) $args;
$post = get_post($args->id);
if ( post_password_required($post) ) {
return __( 'There is no excerpt because this is a protected post.' );
}
$post_content = '<html>' . apply_filters('the_content', $post->post_content) . '</html>';
$post_html = new DOMDocument();
$post_html->loadHTML($post_content);
$paragraphs = $post_html->getElementsByTagName($args->tag);
return $post_html->saveHTML($paragraphs->item($index));
}
After doing that, in your case you could solve your problem by simply using this function in your template, instead of the_excerpt. Like so:
// This gets the third paragraph of your post.
echo my_get_the_excerpt( array( 'idx' => 2 ) )

Answer 3

Put a specific ID on the tag of the paragraph you want to use as an excerpt and when you want to use the excerpt just parse the content of the article and extract only the part in your with the id you've determined.
check this : Get content within a html tag using php and replace it after processing