PHP科學計數法轉換成數字

/**
 * 科學計數法轉換成數字
 * @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;
}