#37: comments_per_page

comments_per_page.php

<?php
/**
 * Increase comments-per-page limit when viewing spam comments
 *
 * @see WP_Comments_List_Table::get_per_page(), WP_Screen::render_per_page_options()
 *
 * @param int $comments_per_page The number of comments to list per page.
 * @param string $comment_status The current comment status view. Default is 'all'.
 *
 * @return int The filtered number of comments to list per page.
 */
function wpdocs_delete_more_spam_comments( $comments_per_page, $comment_status ) {
	if ( 'spam' == $comment_status )
		$comments_per_page = 50;

	return $comments_per_page;
}
add_filter( 'comments_per_page', 'wpdocs_delete_more_spam_comments', 10, 2 );