Using an array as parameter for update script

I am using ElasticSearch 6.8, I want to update many documents at the same time. So I use update by query

` {
"index": "index",

  "type": "type"
  "body":  {
    "query" : {
      "bool" :{
        "must" :{
          "terms" :{
            "id" :[828]
          }
        }
      }
    },
    "script" : {
      "inline" : "ctx._source['number_member'] = params.member[ctx._source['id']]"
      "lang": "painless"
      "params": {
        "member" : [
          828 =>2
        ]
      }
    }
  }
}`

But this params.member [ctx._source ['id']] cannot get a value.
What I have to do. thanks