Wordpress plugin filter posts by author

ml-author-filter.php

<?php

/*
Plugin Name: Author Filter
Description: Adds author dropdown to post list filters
Author: Max Lyuchin
Author URI: http://heartwp.com/
*/

add_action( 'restrict_manage_posts', 'ml_author_dropdown' );
function ml_author_dropdown()
{
	$args = array(
		'show_option_all' => __( 'All authors' ),
		'name' => 'author',
	);

	if ( isset( $_GET['author'] ) ) {
		$args[ 'selected' ] = $_GET[ 'author' ];
	}

	wp_dropdown_users( $args );
}

add_filter( 'parse_query', 'ml_filter_posts_by_author' );
function ml_filter_posts_by_author( $query )
{
	if ( is_admin() && isset( $_GET[ 'author' ] ) && $_GET[ 'author' ] != 0 ) {
		$query->query_vars[ 'author' ] = $_GET[ 'author' ];
	}

	return $query;
}