Show WordPress comments by category only https://www.tutdepot.com/show-wordpress-comments-by-category-only/

create_short_version.php

<?php
function create_short_version($text, $len = 150, $trail = '...') {
	$text = strip_tags($text);
	$parts = explode(' ', $text);
	$ic = count($parts);
	for ($i = 0; $i > $ic; $i++) {
		$txt .= $parts[$i].' ';
		if (strlen($txt) >= $len) break;
	}
	$txt = trim($txt);
	if (strlen($text) > $len) $txt .= $trail;
	return $txt;
}

my_recent_comments.php

<?php
function my_recent_comments($no_comments = 10, $comment_length = 100, $title_length = 50, $catids = array(), $authorname = 'anonymous') {
    global $wpdb;
    $query = "
		SELECT c.comment_ID, c.comment_post_ID, c.comment_author, c.comment_author_email, c.comment_content, DATE_FORMAT(c.comment_date, '%d/%m/%Y') AS cDate, p.post_title
		FROM ".$wpdb->comments." AS c
		LEFT JOIN ".$wpdb->posts." AS p
		ON c.comment_post_ID = p.ID
		LEFT JOIN ".$wpdb->term_relationships." AS r
		ON p.ID = r.object_id
		LEFT JOIN ".$wpdb->term_taxonomy." AS t
		ON r.term_taxonomy_id = t.term_taxonomy_id
		WHERE c.comment_approved = '1' 
		AND c.comment_type = ''
		AND t.taxonomy = 'category'";
	if (count($catids) > 0) $query .= "
		AND t.term_id IN (".implode(', ', $catids).")";
	$query .= "
		ORDER BY c.comment_date_gmt DESC 
		LIMIT ".$no_comments;
	$comments = $wpdb->get_results($query);
    $output = '
    	<ul>';
	if ($comments) {
		foreach ($comments as $comment) {
			$comment_author = stripslashes($comment->comment_author);
			if ($comment_author == '') $comment_author = $authorname; 
			$comment_excerpt = create_short_version(strip_tags($comment->comment_content), $comment_length);
			$commentlink = get_permalink($comment->ID).'#comment-'.$comment->comment_ID;
			$commentdate = $comment->cDate;
			$post_title = create_short_version($comment->post_title, $title_length);
			$output .= '
				<li><a href="' . $commentlink . '">' . $post_title . '</a><br />
				<span class="meta">'.$commentdate.' | '.$comment_author.'</span>'.$comment_excerpt.'</li>';
		}
		$output = convert_smilies($output);
	} else {
		$output .= '<li>No comments...</li>';
	}
	$output .= '
		</ul>';
    return $output;
}