wp_get_current_commenter() 返回一个数组\'comment_author\' 存储名称：

Array (
    [\'comment_author\']       => \'Harriet Smith,
    [\'comment_author_email\'] => \'hsmith@,example.com\',
    [\'comment_author_url\']   => \'http://example.com/\'
)

Update

/**
 * Searches the user table by display name.
 * @param string $display_name
 * @return object
 */
function get_user_by_display_name( $display_name )
{
    global $wpdb;
    $user = $wpdb->get_row( 
        $wpdb->prepare("SELECT * FROM $wpdb->users WHERE display_name = %s", $display_name) 
    );

    if ( ! $user )
    {
        return FALSE;
    }

    _fill_user($user);

    return $user;
}

// Usage:
if ( $userdata = get_user_by_display_name( \'Thomas Scholz\' ) )
{
    print $userdata->user_nicename;
}