在Go语言中递归迭代结构体数组。

huangapple
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英文:

recursively iterate struct array in Go

问题

我需要遍历一个JSON文件中的所有答案选项：

  1. {
  2.   "questions": [
  3.     {
  4.       "id": 1,
  5.       "question": "What is your marital status?",
  6.       "answer": [
  7.         {
  8.           "text": "Single",
  9.           "next_question": 2
  10.         },
  11.         {
  12.           "text": "Married",
  13.           "next_question": 3
  14.         }
  15.       ]
  16.     },
  17.     {
  18.       "id": 2,
  19.       "question": "Are you planning on getting married next year?",
  20.       "answer": [
  21.         {
  22.           "text": "Yes",
  23.           "next_question": 3
  24.         },
  25.         {
  26.           "text": "No",
  27.           "next_question": 5
  28.         }
  29.       ]
  30.     },
  31.     {
  32.       "id": 3,
  33.       "question": "How long have you been married?",
  34.       "answer": [
  35.         {
  36.           "text": "Less than a year",
  37.           "next_question": 6
  38.         },
  39.         {
  40.           "text": "More than a year",
  41.           "next_question": 4
  42.         }
  43.       ]
  44.     },
  45.     {
  46.       "id": 4,
  47.       "question": "Have you celebrated your one year anniversary?",
  48.       "answer": [
  49.         {
  50.           "text": "Yes",
  51.           "next_question": 7
  52.         },
  53.         {
  54.           "text": "No",
  55.           "next_question": 8
  56.         }
  57.       ]
  58.     }
  59.   ]
  60. }

并将路径和编号写入，例如：

  1. {
  2.   "paths": {
  3.     "number": 3,
  4.     "list": [
  5.       [
  6.         {
  7.           "What is your marital status?": "Single"
  8.         },
  9.         {
  10.           "Are you planning on getting married next year?": "Yes/No"
  11.         }
  12.       ],
  13.       [
  14.         {
  15.           "What is your marital status?": "Married"
  16.         },
  17.         {
  18.           "How long have you been married?": "Less than a year"
  19.         }
  20.       ],
  21.       [
  22.         {
  23.           "What is your marital status?": "Married"
  24.         },
  25.         {
  26.           "How long have you been married?": "More than a year"
  27.         },
  28.         {
  29.           "Have you celebrated your one year anniversary?": "Yes/No"
  30.         }
  31.       ]
  32.     ]
  33.   }
  34. }

你可以根据需要更改JSON结构，但主要是显示所有可能的调查路径数量（paths.number），以及按问题序列和答案显示的所有可能路径（paths.list）。

所以，我将JSON解析为以下结构：

  1. type (
  2.    Answer struct {
  3.       Text         string `json:"text"`
  4.       NextQuestion int    `json:"next_question"`
  5.    }
  6.    Question struct {
  7.       Id       int      `json:"id"`
  8.       Question string   `json:"question"`
  9.       Answer   []Answer `json:"answer"`
  10.    }
  11.    Input struct {
  12.       Questions []Question `json:"questions"`
  13.    }
  14. )

然后尝试进行迭代：

  1. func (input Input) Script(itterQuestion []Question, element Question) []Question {
  2.    itterQuestion = append(itterQuestion, element)
  3.    for i, item := range input.Questions {
  4.       if item.Id != itterQuestion[i].Id {
  5.          itterQuestion = append(itterQuestion, item)
  6.       } else {
  7.          return input.Script(itterQuestion, item)
  8.       }
  9.    }
  10.    return itterQuestion
  11. }

但我不明白如何正确编写递归函数和输出结构以生成JSON。

英文:

I need to iterate over all the answer options from a json file:

  1. {"questions": [
  2.   {"id": 1,
  3.     "question": "What is your marital status?",
  4.       "answer":[ {
  5.         "text": "Single",
  6.         "next_question": 2
  7.       },
  8.         {
  9.         "text": "Married",
  10.         "next_question": 3
  11.       }]
  12.     },
  13.   {"id":2,
  14.     "question": "Are you planning on getting married next year?",
  15.     "answer":[{
  16.       "text": "Yes",
  17.       "next_question": 3
  18.       },
  19.       {
  20.       "text": "No",
  21.       "next_question": 5
  22.     }]},
  23.   {"id":3,
  24.     "question": "How long have you been married?",
  25.     "answer": [{
  26.       "text": "Less than a year",
  27.       "next_question": 6
  28.     },
  29.     {
  30.       "text": "More than a year",
  31.       "next_question": 4
  32.     }]},
  33.   {"id":4,
  34.     "question":"Have you celebrated your one year anniversary?",
  35.     "answer": [{
  36.       "text": "Yes",
  37.       "next_question": 7
  38.     },
  39.      {
  40.       "text": "No",
  41.       "next_question": 8
  42.     }]}
  43. ]}

and write the paths and number, like:

  1. {"paths": {"number": 3, "list": [
  2.   [{"What is your marital status?": "Single"},
  3.     {"Are you planning on getting married next year?": "Yes/No"}],
  4.   [{"What is your marital status?": "Married"},
  5.     {"How long have you been married?": "Less than a year"}],
  6.   [{"What is your marital status?": "Married"},
  7.     {"How long have you been married?": "More than a year"},
  8.     {"Have you celebrated your one year anniversary?": "Yes/No"}]
  9. ]}}

You can change JSON structure like you want, but the main thing is to display information about the number of all possible poll paths (paths.number), and all possible paths by a sequence of questions with answers (paths.list)

So, I parse JSON into this structs:

  1. type (
  2.    Answer struct {
  3.       Text         string `json:"text"`
  4.       NextQuestion int    `json:"next_question"`
  5.    }
  6.    Question struct {
  7.       Id       int      `json:"id"`
  8.       Question string   `json:"question"`
  9.       Answer   []Answer `json:"answer"`
  10.    }
  11.    Input struct {
  12.       Questions []Question `json:"questions"`
  13.    }
  14. )

And try to iterate:

  1. func (input Input) Script(itterQuestion []Question, element Question) []Question {
  2.    itterQuestion = append(itterQuestion, element)
  3.    for i, item := range input.Questions {
  4.       if item.Id != itterQuestion[i].Id {
  5.          itterQuestion = append(itterQuestion, item)
  6.         
  7.       } else {
  8.          return input.Script(itterQuestion, item)
  9.       }
  10.    }
  11.    return itterQuestion
  12. }

But I don't understand how to correctly write recursive func and output struct for json.

答案1

得分: 0

由于您想创建多个路径，所以需要使用[][]Question。
此外，您需要将递归函数的结果附加到返回值中，而不仅仅是返回结果。

以下是一个可行的示例：

  1. func (input Input) Script(id int) (out [][]Question) {
  2. 	for _, q := range input.Questions {
  3. 		if q.Id == id {
  4. 			added := false // 避免最后多次添加
  5. 			for _, answer := range q.Answer {
  6. 				paths := input.Script(answer.NextQuestion)
  7. 				if len(paths) == 0 && !added {
  8. 					// 答案没有下一个问题 | 输入中找不到问题
  9. 					out = append(out, []Question{q})
  10. 					added = true
  11. 				}
  12. 				for _, path := range paths {
  13. 					// 在递归函数的每个路径前添加问题
  14. 					path = append([]Question{q}, path...)
  15. 					out = append(out, path)
  16. 				}
  17. 			}
  19. 			return out
  20. 		}
  21. 	}
  22. 	return out
  23. }

希望对您有所帮助！

英文:

Since you want to create multiple paths there is gotta be [][]Question.
Also you have to append result from recursive function instead just returning.

Here's working example:

  1. func (input Input) Script (id int) (out [][]Question) {
  2. 	for _, q := range input.Questions {
  3. 		if q.Id == id {
  4. 			added := false // avoid add last multiple times
  5. 			for _, answer := range q.Answer {
  6. 				paths := input.Script(answer.NextQuestion)
  7. 				if len(paths) == 0  && !added {
  8.                     // answer has no next question | question not found in input
  9. 					out = append(out, []Question{q})
  10. 					added = true
  11. 				}
  12. 				for _, path := range paths {
  13. 					// prepend question to every path from recursive function
  14. 					path = append([]Question{q}, path...)
  15. 					out = append(out, path)
  16. 				}
  17. 			}
  19. 			return out
  20. 		}
  21. 	}
  22. 	return out
  23. }

huangapple
  • 本文由 发表于 2022年3月25日 22:38:38
  • 转载请务必保留本文链接：https://go.coder-hub.com/71618744.html
  • go
  • json
  • recursion
  • struct
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