英文:
Type assert a nested interface
问题
我将JSON解析为interface{}。我无法对其进行类型断言。http://play.golang.org/p/NAe8voYnb8。
package mainimport ("encoding/json""log")func main() {b := []byte(`{"key1":[{"apple":"A", "banana":"B", "id": "C"},{"cupcake": "C", "pinto":"D"}]}`)var data interface{}_ = json.Unmarshal(b, &data)log.Println(data)// map[key1:[map[apple:A id:C banana:B] map[cupcake:C pinto:D]]]ndata, ok := data.(map[string][]map[string]string)log.Println(ok, ndata)// false map[]key_data, ok := ndata["key1"].([]map[string]string)log.Println(ok, key_data)// false []}
有人知道出了什么问题吗？
英文:
I json.Unmarshal JSON into an interface{}. I can't type assert it. http://play.golang.org/p/NAe8voYnb8.
package mainimport ("encoding/json""log")func main() {b := []byte(`{"key1":[{"apple":"A", "banana":"B", "id": "C"},{"cupcake": "C", "pinto":"D"}]}`)var data interface{}_ = json.Unmarshal(b, &data)log.Println(data)// map[key1:[map[apple:A id:C banana:B] map[cupcake:C pinto:D]]]ndata, ok := data.(map[string][]map[string]string)log.Println(ok, ndata)// false map[]key_data, ok := ndata["key1"].([]map[string]string)log.Println(ok, key_data)// false []}
Anyone know what's up?
答案1
得分: 5
例如，
package mainimport ("encoding/json""log")func somefunc(data interface{}) {log.Printf("%T\n", data)// 输出：map[string]interface {}log.Println(data)// 正确输出：map[key1:[map[apple:A id:C banana:B] map[cupcake:C pinto:D]]]ndata, _ := data.(map[string]interface{})log.Println(ndata)// 应该输出：map[key1:[map[apple:A banana:B id:C] map[cupcake:C pinto:D]]]key_data, _ := ndata["key1"]log.Println(key_data)// 应该输出：[map[apple:A banana:B id:C] map[cupcake:C pinto:D]]]}func main() {b := []byte(`{"key1":[{"apple":"A", "banana":"B", "id": "C"},{"cupcake": "C", "pinto":"D"}]}`)var m interface{}_ = json.Unmarshal(b, &m)somefunc(m)}
输出：
2012/10/18 18:21:43 map[string]interface {}2012/10/18 18:21:43 map[key1:[map[apple:A id:C banana:B] map[cupcake:C pinto:D]]]2012/10/18 18:21:43 map[key1:[map[banana:B apple:A id:C] map[pinto:D cupcake:C]]]2012/10/18 18:21:43 [map[banana:B apple:A id:C] map[pinto:D cupcake:C]]
英文:
For example,
package mainimport ("encoding/json""log")func somefunc(data interface{}) {log.Printf("%T\n", data)// Prints: map[string]interface {}log.Println(data)// Correctly prints: map[key1:[map[apple:A id:C banana:B] map[cupcake:C pinto:D]]]ndata, _ := data.(map[string]interface{})log.Println(ndata)// Should print: map[key1:[map[apple:A banana:B id:C] map[cupcake:C pinto:D]]]key_data, _ := ndata["key1"]log.Println(key_data)// Should print: [map[apple:A banana:B id:C] map[cupcake:C pinto:D]]]}func main() {b := []byte(`{"key1":[{"apple":"A", "banana":"B", "id": "C"},{"cupcake": "C", "pinto":"D"}]}`)var m interface{}_ = json.Unmarshal(b, &m)somefunc(m)}
Output:
2012/10/18 18:21:43 map[string]interface {}2012/10/18 18:21:43 map[key1:[map[apple:A id:C banana:B] map[cupcake:C pinto:D]]]2012/10/18 18:21:43 map[key1:[map[banana:B apple:A id:C] map[pinto:D cupcake:C]]]2012/10/18 18:21:43 [map[banana:B apple:A id:C] map[pinto:D cupcake:C]]
答案2
得分: 1
如果你需要一种简单的处理嵌套JSON数据的方法，我已经编写了一个包来实现这个功能：
https://github.com/opesun/jsonp
这可以减轻在每个级别上都需要输入assert的痛苦。请参阅文档以获取描述。
英文:
If you need an easy way to handle nested JSON data, I have written a package to do that:
https://github.com/opesun/jsonp
This alleviates the pain of having to type assert at every level. See the docs for description.
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论