/**獲取Unix毫秒時間戳
     * @return float Unix毫秒時間戳
     */
    function msectime()
    {
        list($msec, $sec) = explode(' ', microtime());
        return (float)sprintf('%.0f', (floatval($msec) + floatval($sec)) * 1000);
    }

其中%.0f是什麼意思呢？看下面的例子

sprintf( "%f \n ", 123.4567 );      // Displays "123.456700" (default precision) 
sprintf( "%.2f \n ", 123.4567 );  // Displays "123.46" 
sprintf( "%.0f \n ", 123.4567 );  // Displays "123" 
sprintf( "%.10f \n ", 123.4567 ); // Displays "123.4567000000"