diff --git a/src/wp-admin/includes/ajax-actions.php b/src/wp-admin/includes/ajax-actions.php
index a04de73bd64e4..3cda30f0d523f 100644
--- a/src/wp-admin/includes/ajax-actions.php
+++ b/src/wp-admin/includes/ajax-actions.php
@@ -128,7 +128,7 @@ function wp_ajax_ajax_tag_search() {
 
 	if ( str_contains( $search, ',' ) ) {
 		$search = explode( ',', $search );
-		$search = $search[ count( $search ) - 1 ];
+		$search = array_last( $search );
 	}
 
 	$search = trim( $search );
diff --git a/src/wp-includes/class-wp-block-parser.php b/src/wp-includes/class-wp-block-parser.php
index 8c619a7b47f2c..ea66e3b51d38d 100644
--- a/src/wp-includes/class-wp-block-parser.php
+++ b/src/wp-includes/class-wp-block-parser.php
@@ -342,7 +342,7 @@ public function add_freeform( $length = null ) {
 	 * @param int|null              $last_offset  Last byte offset into document if continuing form earlier output.
 	 */
 	public function add_inner_block( WP_Block_Parser_Block $block, $token_start, $token_length, $last_offset = null ) {
-		$parent                       = $this->stack[ count( $this->stack ) - 1 ];
+		$parent                       = $this->stack[ array_key_last( $this->stack ) ];
 		$parent->block->innerBlocks[] = (array) $block;
 		$html                         = substr( $this->document, $parent->prev_offset, $token_start - $parent->prev_offset );
 
diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 244cf84e9b810..fc698b343e138 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -2430,11 +2430,12 @@ public function get_posts() {
 
 		if ( '' !== $query_vars['author_name'] ) {
 			if ( str_contains( $query_vars['author_name'], '/' ) ) {
-				$query_vars['author_name'] = explode( '/', $query_vars['author_name'] );
-				if ( $query_vars['author_name'][ count( $query_vars['author_name'] ) - 1 ] ) {
-					$query_vars['author_name'] = $query_vars['author_name'][ count( $query_vars['author_name'] ) - 1 ]; // No trailing slash.
+				$author_name_parts = explode( '/', $query_vars['author_name'] );
+				$last_part         = array_last( $author_name_parts );
+				if ( $last_part ) {
+					$query_vars['author_name'] = $last_part; // No trailing slash.
 				} else {
-					$query_vars['author_name'] = $query_vars['author_name'][ count( $query_vars['author_name'] ) - 2 ]; // There was a trailing slash.
+					$query_vars['author_name'] = $author_name_parts[ count( $author_name_parts ) - 2 ]; // There was a trailing slash.
 				}
 			}
 			$query_vars['author_name'] = sanitize_title_for_query( $query_vars['author_name'] );
diff --git a/src/wp-includes/class-wp-theme-json.php b/src/wp-includes/class-wp-theme-json.php
index 82b8e89de509c..7e2cb54731b1f 100644
--- a/src/wp-includes/class-wp-theme-json.php
+++ b/src/wp-includes/class-wp-theme-json.php
@@ -3994,7 +3994,7 @@ public function get_styles_for_block( $block_metadata ) {
 		 */
 		$is_processing_element = in_array( 'elements', $block_metadata['path'], true );
 
-		$current_element = $is_processing_element ? $block_metadata['path'][ count( $block_metadata['path'] ) - 1 ] : null;
+		$current_element = $is_processing_element ? array_last( $block_metadata['path'] ) : null;
 
 		$element_pseudo_allowed = array();
 
@@ -4688,7 +4688,7 @@ public static function remove_insecure_properties( $theme_json, $origin = 'theme
 			 * Get a reference to element name from path.
 			 * $metadata['path'] = array( 'styles', 'elements', 'link' );
 			 */
-			$current_element = $metadata['path'][ count( $metadata['path'] ) - 1 ];
+			$current_element = array_last( $metadata['path'] );
 
 			/*
 			 * $output is stripped of pseudo selectors. Re-add and process them
diff --git a/src/wp-includes/pomo/plural-forms.php b/src/wp-includes/pomo/plural-forms.php
index a604334e88c20..cc31471a0b88d 100644
--- a/src/wp-includes/pomo/plural-forms.php
+++ b/src/wp-includes/pomo/plural-forms.php
@@ -128,7 +128,7 @@ protected function parse( $str ) {
 					case ')':
 						$found = false;
 						while ( ! empty( $stack ) ) {
-							$o2 = $stack[ count( $stack ) - 1 ];
+							$o2 = array_last( $stack );
 							if ( '(' !== $o2 ) {
 								$output[] = array( 'op', array_pop( $stack ) );
 								continue;
@@ -163,7 +163,7 @@ protected function parse( $str ) {
 						}
 
 						while ( ! empty( $stack ) ) {
-							$o2 = $stack[ count( $stack ) - 1 ];
+							$o2 = array_last( $stack );
 
 							// Ternary is right-associative in C.
 							if ( '?:' === $operator || '?' === $operator ) {
diff --git a/src/wp-trackback.php b/src/wp-trackback.php
index 76c2a1d4a7285..c666c13e8b823 100644
--- a/src/wp-trackback.php
+++ b/src/wp-trackback.php
@@ -50,7 +50,7 @@ function trackback_response( $error = 0, $error_message = '' ) {
 
 if ( ! isset( $_GET['tb_id'] ) || ! $_GET['tb_id'] ) {
 	$post_id = explode( '/', $_SERVER['REQUEST_URI'] );
-	$post_id = (int) $post_id[ count( $post_id ) - 1 ];
+	$post_id = (int) array_last( $post_id );
 }
 
 $trackback_url = isset( $_POST['url'] ) ? sanitize_url( $_POST['url'] ) : '';