从Json中提取数组中的值

huangapple
go评论103阅读模式
英文:

Extract value from an array in a Json

问题

我正在尝试获取"boots"的值

我的主要函数

  1. var json := `{
  2.   "identifier": "1",
  3.   "name": "dumbname",
  4.   "person": {
  5.     "items": null,
  6.     "inventory": [
  7.       {
  8.         "T-shirt": "black",
  9.         "Backpack": {
  10.           "BigPocket": {
  11.             "spell": "healing",
  12.             "boots": "speed",
  13.             "shampoo": "Head & Shoulders"
  14.           }
  15.         }
  16.       }
  17.     ],
  18.     "Pockets": null
  19.   }
  20. }`
  22. var res map[string]interface{}
  24. json.Unmarshal([]byte(json), &res)
  26. test(res)

测试函数

  1.     func test(t interface{}) {
  2. 	  switch reflect.TypeOf(t).Kind() {
  3. 	   case reflect.Slice:
  4. 		s := reflect.ValueOf(t)
  5. 	for i := 0; i < s.Len(); i++ {
  6. 		fmt.Println(s.Index(i))
  7. 	    }
  8. 	  }
  9.     }

但是当我编译时什么都没有得到
如果有其他方法可以获取Json中的"boot"值吗？

英文:

I'm trying to get "boots" value

My func main

  1. varjson:=`{
  2.   &quot;identifier&quot;: &quot;1&quot;,
  3.   &quot;name&quot;: &quot;dumbname&quot;,
  4.   &quot;person&quot;: {
  5.     &quot;items&quot;: null,
  6.     &quot;inventory&quot;: [
  7.       {
  8.         &quot;T-shirt&quot;: &quot;black&quot;,
  9.         &quot;Backpack&quot;: {
  10.           &quot;BigPocket&quot;: {
  11.             &quot;spell&quot;: &quot;healing&quot;,
  12.             &quot;boots&quot;: &quot;speed&quot;,
  13.             &quot;shampoo&quot;: &quot;Head &amp; Shoulders&quot;
  14.           }
  15.         }
  16.       }
  17.     ],
  18.     &quot;Pockets&quot;: null
  19.   }
  20. }`
  22. var res map[string]interface{}
  24. json.Unmarshal([]byte(varjson), &amp;res)
  26. test(res)

test function

  1.     func test(t interface{}) {
  2. 	  switch reflect.TypeOf(t).Kind() {
  3. 	   case reflect.Slice:
  4. 		s := reflect.ValueOf(t)
  5. 	for i := 0; i &lt; s.Len(); i++ {
  6. 		fmt.Println(s.Index(i))
  7. 	    }
  8. 	  }
  9.     }

But when I compile I get nothing
If is there another way to get the "boot" value in the Json?

答案1

得分: 1

假设你可以使用类型，根据你的评论（幸运的是，我完全同意colm的观点，尝试反映结构是困难的）。

一旦你有了一个类型，导航就非常容易。

具体来说，fmt.Println(res.Person.Inventory[0].Backpack.BigPocket.Boots) 将返回 boots 的值。需要注意的是，Inventory 是一个切片，所以你可能需要遍历它，而我在这里直接访问了它，如果 Inventory 是空的或者有其他元素，这样做是不好的。

  1. package main
  3. import (
  4. 	"encoding/json"
  5. 	"fmt"
  6. )
  8. type AutoGenerated struct {
  9. 	Identifier string `json:"identifier"`
  10. 	Name       string `json:"name"`
  11. 	Person     struct {
  12. 		Items     interface{} `json:"items"`
  13. 		Inventory []struct {
  14. 			TShirt   string `json:"T-shirt"`
  15. 			Backpack struct {
  16. 				BigPocket struct {
  17. 					Spell   string `json:"spell"`
  18. 					Boots   string `json:"boots"`
  19. 					Shampoo string `json:"shampoo"`
  20. 				} `json:"BigPocket"`
  21. 			} `json:"Backpack"`
  22. 		} `json:"inventory"`
  23. 		Pockets interface{} `json:"Pockets"`
  24. 	} `json:"person"`
  25. }
  27. func main() {
  28. 	var varjson = `{
  29. 		"identifier": "1",
  30. 		"name": "dumbname",
  31. 		"person": {
  32. 			"items": null,
  33. 			"inventory": [
  34. 				{
  35. 					"T-shirt": "black",
  36. 					"Backpack": {
  37. 						"BigPocket": {
  38. 							"spell": "healing",
  39. 							"boots": "speed",
  40. 							"shampoo": "Head & Shoulders"
  41. 						}
  42. 					}
  43. 				}
  44. 			],
  45. 			"Pockets": null
  46. 		}
  47. 	}`
  49. 	var res AutoGenerated
  50. 	json.Unmarshal([]byte(varjson), &res)
  52. 	fmt.Println(res.Person.Inventory[0].Backpack.BigPocket.Boots)
  53. }

在你的原始代码中，问题在于你的 switch 语句只覆盖了一个切片，但初始对象是一个映射。所以你的 switch 最初找不到匹配项。

英文:

Assuming you can use types, based on your comment (thankfully cause totally agree with colm, trying to reflect the structure is rough.

Once you have a type its super easy to navigate.

specifically fmt.Println(res.Person.Inventory[0].Backpack.BigPocket.Boots)
would net you the boots value. Bearing in mind that Inventory is a slice so you probably need to iterate over that, whereas here I have directly accessed it, which will be bad if Inventory is empty or there are other elements.

  1. package main
  3. import (
  4. 	&quot;encoding/json&quot;
  5. 	&quot;fmt&quot;
  6. )
  8. type AutoGenerated struct {
  9. 	Identifier string `json:&quot;identifier&quot;`
  10. 	Name       string `json:&quot;name&quot;`
  11. 	Person     struct {
  12. 		Items     interface{} `json:&quot;items&quot;`
  13. 		Inventory []struct {
  14. 			TShirt   string `json:&quot;T-shirt&quot;`
  15. 			Backpack struct {
  16. 				BigPocket struct {
  17. 					Spell   string `json:&quot;spell&quot;`
  18. 					Boots   string `json:&quot;boots&quot;`
  19. 					Shampoo string `json:&quot;shampoo&quot;`
  20. 				} `json:&quot;BigPocket&quot;`
  21. 			} `json:&quot;Backpack&quot;`
  22. 		} `json:&quot;inventory&quot;`
  23. 		Pockets interface{} `json:&quot;Pockets&quot;`
  24. 	} `json:&quot;person&quot;`
  25. }
  27. func main() {
  28. 	varjson := `{
  29.   &quot;identifier&quot;: &quot;1&quot;,
  30.   &quot;name&quot;: &quot;dumbname&quot;,
  31.   &quot;person&quot;: {
  32.     &quot;items&quot;: null,
  33.     &quot;inventory&quot;: [
  34.       {
  35.         &quot;T-shirt&quot;: &quot;black&quot;,
  36.         &quot;Backpack&quot;: {
  37.           &quot;BigPocket&quot;: {
  38.             &quot;spell&quot;: &quot;healing&quot;,
  39.             &quot;boots&quot;: &quot;speed&quot;,
  40.             &quot;shampoo&quot;: &quot;Head &amp; Shoulders&quot;
  41.           }
  42.         }
  43.       }
  44.     ],
  45.     &quot;Pockets&quot;: null
  46.   }
  47. }`
  49. 	var res AutoGenerated
  50. 	json.Unmarshal([]byte(varjson), &amp;res)
  51. 	
  52. 	fmt.Println(res.Person.Inventory[0].Backpack.BigPocket.Boots)
  53. }

In your original, whats wrong is your switch statement only covers a slice, but the initial object is a map. So your switch is not finding a match initially

huangapple
  • 本文由 发表于 2021年9月17日 06:18:46
  • 转载请务必保留本文链接：https://go.coder-hub.com/69215789.html
  • go
  • json
  • reflect
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