title: how to assign value to a get-only property
body: <p>As the movie struct shows as below, I want to upload my <code>vote</code> vault through the <code>upVote</code> function but the error occurs as &quot;Cannot assign to property: 'vote' is a get-only property&quot;.</p>
  <p>Except for the <code>vote</code> and 'isFavored, other properties are all decoded from a local JSON file.</p>
  <p><strong>my struct</strong></p>
  <pre><code>
  struct Movie:Codable,Identifiable{
      let id=UUID()
      let MOVIE_ID:String
      let NAME:String
      let ALIAS:String
      let ACTORS:String
      let COVER:String
      let DIRECTORS:String
      let DOUBAN_SCORE:String
      let DOUBAN_VOTES:String
      let GENRES:String
      let IMDB_ID:String
      let LANGUAGES:String
      let DIRECTOR_IDS:String
  \\my own property:
      var isFavered:Bool = false
  \\init the vote
      var vote:Int{
          if let v = Int(DOUBAN_VOTES){
              return v
          }else{
              return 0
          }
          
      }
      enum CodingKeys: String, CodingKey {
          case MOVIE_ID, NAME,ALIAS,ACTORS,COVER,DIRECTORS,DOUBAN_SCORE
          case DOUBAN_VOTES,GENRES,IMDB_ID,LANGUAGES,MINS,OFFICIAL_SITE
          case REGIONS,RELEASE_DATE,SLUG,STORYLINE,TAGS,YEAR,ACTOR_IDS,DIRECTOR_IDS
      }
  \\my uploade vote function
      func upVote(newVote:Int){
          vote = newVote \\ here occurs the error
      }
  }
  
  </code></pre>