[WordPress] Using a helper function to write a lightweight, easy-to-read way to check if a WordPress post exists given an ID.

get-post-status.php

<?php

/**
 * See: http://codex.wordpress.org/Function_Reference/get_post_status
 *      for more information.
 */
if ( FALSE === get_post_status( $id ) ) {
  // The post does not exist
} else {
  // The post exists
}

post-exists.php

<?php

/**
 * Determines if a post, identified by the specified ID, exist
 * within the WordPress database.
 * 
 * Note that this function uses the 'acme_' prefix to serve as an
 * example for how to use the function within a theme. If this were
 * to be within a class, then the prefix would not be necessary.
 *
 * @param    int    $id    The ID of the post to check
 * @return   bool          True if the post exists; otherwise, false.
 * @since    1.0.0
 */
function acme_post_exists( $id ) {
  return is_string( get_post_status( $id ) );
}