[WordPress] Properly Filtering Post Content (And Understanding apply_filters)

00-my_content.php

<?php

$post->post_content = $my_content;

01-apply-filters.php

<?php

$post->post_content = apply_filters( 'the_content', $my_content );

02-dont-apply-filters.php

<?php

/**
 * Assume $contents is an array of information we want to convert into content for a post.
 */

$new_content = '';
foreach ( $contents as $line ) {

	if ( false === strpos( $line, $name ) ) {
		$new_content .= $line;
	}
}

$post->post_content = $new_content;

03-apply-filters.php

<?php

/**
 * Assume $contents is an array of information we want to convert into content for a post.
 */

$new_content = '';
foreach ( $contents as $line ) {

	if ( false === strpos( $line, $name ) ) {
		$new_content .= $line;
	}
}

$post->post_content = apply_filters( 'the_content', $new_content );