【ワードプレス】管理画面の投稿ページに作成者による絞り込み項目を追加

functions.php

add_action('restrict_manage_posts', function() {
	$selected = ( is_author() ) ? get_query_var( 'author' ) : 0;
	$authors  = get_users(array('fields' => 'ids'));
	
	printf('<label class="screen-reader-text" for="author">%s</label>', __( 'Filter by author' ));
	printf('<select id="filter-by-author" name="author">');
	printf('<option value="0">%s</option>', __('All author'));
	foreach ( $authors as $author_id ) {
		$author = get_userdata( $author_id );
		if($selected == $author->ID){
			printf("<option value='%s' selected>%s</option>", $author->ID, $author->display_name);					}else{
			printf("<option value='%s'>%s</option>", $author->ID, $author->display_name);	
		}
	}
	printf('</selece>');
});