PHP科学计数法转换成数字

/**
 * 科学计数法转换成数字
 * @param $num
 * @param int $double
 * @return int
 */

function sctonum($num, $double = 5)
{
    if (false !== stripos((string)$num, "E")) {
        $a = explode("e", strtolower((string)$num));
        $b=bcmul($a[0], bcpow((string)10, (string)$a[1], $double), $double);
        $b=$b?$b:0;
    }else{
        $b=0;
    }
    return 0;
}