识别不带括号的文本，并带有消极的外观

Question

环回正则表达式无效。

我有格式为

的字符串

public function upload()
   {



//image upload  
     $config['upload_path'] = './images';
     $config['allowed_types'] = 'gif|jpg|png|jpeg';
     $this->load->library('upload',$config);
     $this->upload->initialize($config);

     $fileInfos = array();
     $errors = array();

     //uploading

     if (! empty($_FILES['images']['name'])) 
     {
        $photosCount = count($_FILES['images']['name']);
        for ($i = 0; $i < $photosCount; $i ++)
         {
           $_FILES['image']['name'] = $_FILES['images']['name'][$i];
           $_FILES['image']['type'] = $_FILES['images']['type'][$i];
           $_FILES['image']['tmp_name'] = $_FILES['images']['tmp_name'][$i];
           $_FILES['image']['error'] = $_FILES['images']['error'][$i];
           $_FILES['image']['size'] = $_FILES['images']['size'][$i];
           if ($this->upload->do_upload('image')) 
           {
                    array_push($fileInfos, array(
                        'fileInfo' => $this->upload->data()

                    ));
                  $filename =$_FILES['image']['name'] ;
                    //$filename =$_FILES["name"].$_FILES["type"];

                      //   $data['fileInfos'] = $fileInfo;
                  $this->load->model("ProductmModel");
                        $this->ProductmModel->IMAGE = $filename;


            }
            else 
                {
                    array_push($errors, array(
                        'error' => $this->upload->display_errors()
                    ));
                }


           }


         }


      $pname = $this->input->post("name");
      $pdes = $this->input->post("pdes");
      $caty = $this->input->post("category");
      $subcat = $this->input->post("subcat");

        $this->ProductmModel->PRODUCTNAME = $pname;
        $this->ProductmModel->DESCRIPTION = $pdes;
        $this->ProductmModel->CATEGORY = $caty;
        $this->ProductmModel->SUBCAT = $subcat;
       $this->ProductmModel->addproductm();


     }

我想沿“，”分割，除非“，”位于f（x，y）之类的函数中，即除非被（）包围

我尝试匹配相关的“”，如下：

a,b,f(x,y),c,h(u,v,w),d,e,...

此操作失败，因为回溯的长度不是固定的。然后我尝试了

(?<!\([^\)]*),(?![^\(]*\))

这有效，但是我不明白这里如何解释“ 100”。它似乎不被解释为“恰好100次出现”。真的是怎么做到的？