php 科学计数法转化正常数值输出

/**
 * @param $num         科学计数法字符串
 * @param int $double 小数点保留位数 默认10位
 * @return string
*/
function sctonum($num, $double = 10){
    if(stripos($num, "e") !== false){
        $a = explode('e', strtolower($num));
        $str =  bcmul($a[0], bcpow(10, $a[1], $double), $double);
        return rtrim(rtrim($str, '0'), '.');   //去除小数后多余的0
    }
    return $num;
}

 $obj = '{"id":130126199,"str":0.0000852}';
 $obj = json_decode($obj, TRUE);
 foreach ($obj as $key => $val) {
      // $obj[$key] = number_format($val, 0, '', '');
      $obj[$key] = $this->sctonum($val);
 }
 var_dump($obj);

//输出
array(2) {
  ["id"]=>
  int(130126199)
  ["str"]=>
  string(9) "0.0000852"
}