gjson除了能够灵活解析、检索未知数据结构内容，还能够动态创建和修改数据结构内容。

动态创建

1. 示例1，简单使用

   j := gjson.New(nil)
   j.Set("name", "John")
   j.Set("score", 99.5)
   fmt.Printf(
       "Name: %s, Score: %v\n",
       j.GetString("name"),
       j.GetFloat32("score"),
   )
   fmt.Println(j.MustToJsonString())
   
   
   // Output:
   // Name: John, Score: 99.5
   // {"name":"John","score":99.5}
   

2. 示例2，创建数组

   j := gjson.New(nil)
   for i := 0; i < 5; i++ {
       j.Set(fmt.Sprintf(`%d.id`, i), i)
       j.Set(fmt.Sprintf(`%d.name`, i), fmt.Sprintf(`student-%d`, i))
   }
   fmt.Println(j.MustToJsonString())
   
   
   // Output:
   // [{"id":0,"name":"student-0"},{"id":1,"name":"student-1"},{"id":2,"name":"student-2"},{"id":3,"name":"student-3"},{"id":4,"name":"student-4"}]
   

动态修改

data :=
    `{
    "users" : {
        "count" : 2,
        "list"  : [
            {"name" : "Ming", "score" : 60},
            {"name" : "John", "score" : 59}
        ]
    }
}`
if j, err := gjson.DecodeToJson(data); err != nil {
    panic(err)
} else {
    j.Set("users.list.1.score", 100)
    fmt.Println("John Score:", j.GetFloat32("users.list.1.score"))
    fmt.Println(j.MustToJsonString())
}
// Output:
// John Score: 100
// {"users":{"count":2,"list":[{"name":"Ming","score":60},{"name":"John","score":100}]}}

...