我怎麼能改進這個嵌套邏輯以使其正常工作並提高效能

php小編魚仔，你可能在寫程式碼時遇到了嵌套邏輯的問題，導致程式碼無法正常運作或效能較低。要改進這個問題，有幾個關鍵點需要考慮。首先，你可以重新檢視你的邏輯結構，看看是否可以簡化或重構程式碼，以減少巢狀層級。其次，你可以考慮使用適當的資料結構和演算法來優化你的程式碼。另外，確保你的程式碼沒有重複的計算或冗餘的操作，以提高效能。最後，進行適當的測試和調試，以確保你的程式碼在各種情況下都能正常運作。透過這些方法，你可以改進嵌套邏輯並提高程式碼的效能。

問題內容

我有一個包含評論的資料庫，每個評論都有一個 ID 和一個父 ID。目標只是以高效的方式將帶有父 ID 的每個評論放在其父評論下。

我最初使用遞歸函數在 arranged 陣列中搜尋父註釋，但效能很糟糕。我重構為使用指標來追蹤父母，這幾乎完美地工作，但似乎最後要處理的評論總是被排除在輸出之外。

在下面的範例中，「comment 1」應該是「comment 11」的子級，但它根本不包含在輸出中。

package main

import (
  "encoding/json"
  "fmt"
)

// Comment from Database
type Comment struct {
  ID       string `json:"id""`
  ParentID string `json:"pid"`
  Text     string `json:"text"`
}

// NestedComment output
type NestedComment struct {
  Comment
  Children []NestedComment `json:"children,omitempty"`
}

func main() {
  // Some comment data from DB
  jsondata := `[{"id":"f1c3a838-f4b4-4ebd-bb1b-d3e4c0dce27d","pid":"6a162b3f-9341-46e9-95f7-dedc6cd06868","text":"comment 1"},{"id":"131cf4bb-1971-43a2-992f-2cbb042a4184","pid":"","text":"comment 2"},{"id":"4c93a789-ecab-4173-954c-b039cd3a9e17","pid":"131cf4bb-1971-43a2-992f-2cbb042a4184","text":"comment 3"},{"id":"c7974b6d-67e1-47d0-84fa-c78d51682df2","pid":"131cf4bb-1971-43a2-992f-2cbb042a4184","text":"comment 4"},{"id":"386c4439-4596-47c1-99bf-cb479055fe5a","pid":"","text":"comment 5"},{"id":"5ef0816e-ea13-4a7e-8009-e67ee08ef906","pid":"386c4439-4596-47c1-99bf-cb479055fe5a","text":"comment 6"},{"id":"96b0a536-602b-4f3f-a352-020f22cdfb18","pid":"","text":"comment 7"},{"id":"d0f11e98-deea-4fd5-becb-8f406ebcae83","pid":"96b0a536-602b-4f3f-a352-020f22cdfb18","text":"comment 8"},{"id":"bad87461-3cbf-4ecb-a8c7-36876b57d652","pid":"","text":"comment 9"},{"id":"e3ee6f90-495f-4348-9c29-bd6e15ec3b39","pid":"bad87461-3cbf-4ecb-a8c7-36876b57d652","text":"comment 10"},{"id":"6a162b3f-9341-46e9-95f7-dedc6cd06868","pid":"","text":"comment 11"},{"id":"041c7c2d-0688-491e-b6cd-899eac95bd3d","pid":"","text":"comment 12"},{"id":"5acdf3ff-345b-47a5-bd66-a6687a1441b7","pid":"041c7c2d-0688-491e-b6cd-899eac95bd3d","text":"comment 13"},{"id":"aaee2ae5-7e3a-4435-a094-83bf6b77abfb","pid":"","text":"comment 14"},{"id":"6108b28c-a7af-4c5a-a38c-c22db0d34b31","pid":"aaee2ae5-7e3a-4435-a094-83bf6b77abfb","text":"comment 15"},{"id":"1736393e-95b0-4f5d-a149-50fe52c28350","pid":"","text":"comment 16"},{"id":"b646f202-17aa-4af9-b8dc-c1d8ff3529ac","pid":"1736393e-95b0-4f5d-a149-50fe52c28350","text":"comment 17"},{"id":"a8827b1d-fdbc-41c2-bdb5-38e8b308dedc","pid":"b646f202-17aa-4af9-b8dc-c1d8ff3529ac","text":"comment 18"},{"id":"76e49597-6039-4cb5-a595-556ccc2e3c12","pid":"a8827b1d-fdbc-41c2-bdb5-38e8b308dedc","text":"comment 19"},{"id":"07dc4b90-65d3-4f75-8351-457305988235","pid":"76e49597-6039-4cb5-a595-556ccc2e3c12","text":"comment 20"},{"id":"2d4e838b-82df-4ca0-bf9b-f1dfb99d6763","pid":"07dc4b90-65d3-4f75-8351-457305988235","text":"comment 21"},{"id":"617c1760-0dca-409c-af2a-c614f0530e07","pid":"","text":"comment 22"},{"id":"712c0b7e-a9e4-40fd-ab78-c39b483b1435","pid":"617c1760-0dca-409c-af2a-c614f0530e07","text":"comment 23"},{"id":"e325094c-886e-42c9-bd59-fdd7a189b384","pid":"","text":"comment 24"},{"id":"f3b8b0f9-edef-4ee6-9555-42e8595f854c","pid":"e325094c-886e-42c9-bd59-fdd7a189b384","text":"comment 25"},{"id":"6e09a231-a2ee-4aa1-a898-57695e6fe153","pid":"","text":"comment 26"},{"id":"63e629d6-c0f9-4b36-ad96-e0c47cf8bb4e","pid":"6e09a231-a2ee-4aa1-a898-57695e6fe153","text":"comment 27"},{"id":"d7b698f1-8757-46db-a6e6-5141a481b42b","pid":"","text":"comment 28"},{"id":"a7e3d522-553c-44f1-befa-047bd94f0e59","pid":"","text":"comment 29"},{"id":"fe78ce24-c2c8-4d00-b96d-8b8be9ce0f06","pid":"","text":"comment 30"},{"id":"fabdccb5-a024-4476-bd51-7d55fb685c42","pid":"","text":"comment 31"},{"id":"608d0693-6e43-46a0-9e54-107da6adb109","pid":"fabdccb5-a024-4476-bd51-7d55fb685c42","text":"comment 32"}]`

  var comments []Comment

  err := json.Unmarshal([]byte(jsondata), &comments)
  if err != nil {
    panic(err)
  }

  arranged := ArrangeComments(comments, len(comments))

  arrangedjson, _ := json.MarshalIndent(arranged, "", "  ")

  fmt.Println(string(arrangedjson))
  fmt.Println("comments", len(comments), "arranged", recursiveCount(arranged))
}

func recursiveCount(arranged []NestedComment) int {
    count := len(arranged)
    for _, item := range arranged {
        count += recursiveCount(item.Children)
    }
    return count
}

// Nesting function -------------------------------------------------------------------------

func ArrangeComments(queue []Comment, count int) []NestedComment {
  var arranged []NestedComment

  // using pointers over a recursive search
  var refs []*NestedComment

  // some comments are orphaned, se we need a bail out
  tries := 0
  maxTries := 5
  prevPlacedLen := 0

  // IDs of placed comments
  var placed []string

  // while count is greater then length of placed
countloop:
  for count > len(placed) {
    // loop through queue
  queueloop:
    for _, item := range queue {

      // skip if already placed
      if len(placed) > 0 {
        for _, id := range placed {
          if id == item.ID {
            continue queueloop
          }
        }
      }

      // if parent is nil, add to arranged
      if item.ParentID == "" {
        arranged = append(arranged, NestedComment{
          Comment: item,
        })
        refs = append(refs, &arranged[len(arranged)-1])
        placed = append(placed, item.ID)
      } else {
        // if parent is not nil, loop through refs and add to children
      refloop:
        for _, ref := range refs {
          if ref.ID == item.ParentID {
            ref.Children = append(ref.Children, NestedComment{Comment: item})
            refs = append(refs, &ref.Children[len(ref.Children)-1])
            placed = append(placed, item.ID)
            break refloop
          }
        }
      }
    }

    // if no comments were placed, bail out after x tries
    if len(placed) == prevPlacedLen {
      if tries >= maxTries {
        break countloop
      }
      tries++
      break
    }

    prevPlacedLen = len(placed)
  }

  return arranged
}

更新；這讓我更接近，但無法嵌套一些更深層的嵌套評論。奇怪的是，它每次運行時都會產生不同的輸出：

func ArrangeComments(comments []Comment) []NestedComment {
    // Map to hold references to NestedComment by their ID
    queue := make(map[string]*NestedComment)

    // Result slice
    var result []NestedComment

    // First, create all NestedComments and store references in the map
    for _, comment := range comments {
        nc := &NestedComment{Comment: comment}
        queue[comment.ID] = nc
    }

    // Second, loop through the map and add children to their parents
    for _, comment := range queue {
        if comment.ParentID != "" {
            parent := queue[comment.Comment.ParentID]
            if parent != nil {
                parent.Children = append(parent.Children, *comment)
            }
        }
    }

    // Third, loop through the map and add all root comments to the result slice
    for _, comment := range queue {
        if comment.ParentID == "" {
            result = append(result, *comment)
        }
    }

    return result
}

更新；我快速編寫了一個 JavaScript 實現，它可以在給定相同範例資料的情況下產生正確的結果，但我無法弄清楚為什麼此 JS 程式碼可以工作而 Go 程式碼不起作用。

const datajson = `[{"id":"f1c3a838-f4b4-4ebd-bb1b-d3e4c0dce27d","pid":"6a162b3f-9341-46e9-95f7-dedc6cd06868","text":"comment 1"},{"id":"131cf4bb-1971-43a2-992f-2cbb042a4184","pid":"","text":"comment 2"},{"id":"4c93a789-ecab-4173-954c-b039cd3a9e17","pid":"131cf4bb-1971-43a2-992f-2cbb042a4184","text":"comment 3"},{"id":"c7974b6d-67e1-47d0-84fa-c78d51682df2","pid":"131cf4bb-1971-43a2-992f-2cbb042a4184","text":"comment 4"},{"id":"386c4439-4596-47c1-99bf-cb479055fe5a","pid":"","text":"comment 5"},{"id":"5ef0816e-ea13-4a7e-8009-e67ee08ef906","pid":"386c4439-4596-47c1-99bf-cb479055fe5a","text":"comment 6"},{"id":"96b0a536-602b-4f3f-a352-020f22cdfb18","pid":"","text":"comment 7"},{"id":"d0f11e98-deea-4fd5-becb-8f406ebcae83","pid":"96b0a536-602b-4f3f-a352-020f22cdfb18","text":"comment 8"},{"id":"bad87461-3cbf-4ecb-a8c7-36876b57d652","pid":"","text":"comment 9"},{"id":"e3ee6f90-495f-4348-9c29-bd6e15ec3b39","pid":"bad87461-3cbf-4ecb-a8c7-36876b57d652","text":"comment 10"},{"id":"6a162b3f-9341-46e9-95f7-dedc6cd06868","pid":"","text":"comment 11"},{"id":"041c7c2d-0688-491e-b6cd-899eac95bd3d","pid":"","text":"comment 12"},{"id":"5acdf3ff-345b-47a5-bd66-a6687a1441b7","pid":"041c7c2d-0688-491e-b6cd-899eac95bd3d","text":"comment 13"},{"id":"aaee2ae5-7e3a-4435-a094-83bf6b77abfb","pid":"","text":"comment 14"},{"id":"6108b28c-a7af-4c5a-a38c-c22db0d34b31","pid":"aaee2ae5-7e3a-4435-a094-83bf6b77abfb","text":"comment 15"},{"id":"1736393e-95b0-4f5d-a149-50fe52c28350","pid":"","text":"comment 16"},{"id":"b646f202-17aa-4af9-b8dc-c1d8ff3529ac","pid":"1736393e-95b0-4f5d-a149-50fe52c28350","text":"comment 17"},{"id":"a8827b1d-fdbc-41c2-bdb5-38e8b308dedc","pid":"b646f202-17aa-4af9-b8dc-c1d8ff3529ac","text":"comment 18"},{"id":"76e49597-6039-4cb5-a595-556ccc2e3c12","pid":"a8827b1d-fdbc-41c2-bdb5-38e8b308dedc","text":"comment 19"},{"id":"07dc4b90-65d3-4f75-8351-457305988235","pid":"76e49597-6039-4cb5-a595-556ccc2e3c12","text":"comment 20"},{"id":"2d4e838b-82df-4ca0-bf9b-f1dfb99d6763","pid":"07dc4b90-65d3-4f75-8351-457305988235","text":"comment 21"},{"id":"617c1760-0dca-409c-af2a-c614f0530e07","pid":"","text":"comment 22"},{"id":"712c0b7e-a9e4-40fd-ab78-c39b483b1435","pid":"617c1760-0dca-409c-af2a-c614f0530e07","text":"comment 23"},{"id":"e325094c-886e-42c9-bd59-fdd7a189b384","pid":"","text":"comment 24"},{"id":"f3b8b0f9-edef-4ee6-9555-42e8595f854c","pid":"e325094c-886e-42c9-bd59-fdd7a189b384","text":"comment 25"},{"id":"6e09a231-a2ee-4aa1-a898-57695e6fe153","pid":"","text":"comment 26"},{"id":"63e629d6-c0f9-4b36-ad96-e0c47cf8bb4e","pid":"6e09a231-a2ee-4aa1-a898-57695e6fe153","text":"comment 27"},{"id":"d7b698f1-8757-46db-a6e6-5141a481b42b","pid":"","text":"comment 28"},{"id":"a7e3d522-553c-44f1-befa-047bd94f0e59","pid":"","text":"comment 29"},{"id":"fe78ce24-c2c8-4d00-b96d-8b8be9ce0f06","pid":"","text":"comment 30"},{"id":"fabdccb5-a024-4476-bd51-7d55fb685c42","pid":"","text":"comment 31"},{"id":"608d0693-6e43-46a0-9e54-107da6adb109","pid":"fabdccb5-a024-4476-bd51-7d55fb685c42","text":"comment 32"}]`

const queue = JSON.parse(datajson)

const result = []

const queueMap = new Map(queue.map(item => [item.id, item]))

for (const item of queue) {
  if (item.pid !== '') {
    const parent = queueMap.get(item.pid)
    if (parent) {
      if (!parent.children) {
        parent.children = []
      }
      parent.children.push(item)
    }
  }
}

for (const [_, value] of queueMap) {
  if (value.pid === '') {
    result.push(value)
  }
}

function recursiveCount(res) {
  let count = res.length
  res.forEach(item => {
    if (item.children) {
      count += recursiveCount(item.children)
    }
  });
  return count
}


console.log(JSON.stringify(result, null, 2))
console.log("comments", queue.length, "arranged", recursiveCount(result))

可運作的 Go 範例：https://gist.github.com/dlford/9e66069cfc7fb9afc649c5e3dc650083

可運作的 JS 範例：https://gist.github.com/dlford/f6f4a383a99f65659895ed51d1a4b651

Go 程式碼輸出（請參閱底部的計數）：https://gist.github.com/dlford/302c4db939c21d15132848368caa01ec

JS 程式碼輸出（請參閱底部的計數）：https://gist.github.com/dlford/60ab49d0466c957c7745059022e27e09

解決方法

問題是NestedCommentNestedComment#問題是

NestedComment

中的

Children### 也需要儲存為指標。 ### ###工作範例：###

package main

import (
    "encoding/json"
    "fmt"
)

// Comment from Database
type Comment struct {
    ID       string `json:"id"`
    ParentID string `json:"pid"`
    Text     string `json:"text"`
}

// NestedComment output
type NestedComment struct {
    Comment
    Children []*NestedComment `json:"children,omitempty"`
}

func main() {
    // Some comment data from DB
    jsondata := `[{"id":"f1c3a838-f4b4-4ebd-bb1b-d3e4c0dce27d","pid":"6a162b3f-9341-46e9-95f7-dedc6cd06868","text":"comment 1"},{"id":"131cf4bb-1971-43a2-992f-2cbb042a4184","pid":"","text":"comment 2"},{"id":"4c93a789-ecab-4173-954c-b039cd3a9e17","pid":"131cf4bb-1971-43a2-992f-2cbb042a4184","text":"comment 3"},{"id":"c7974b6d-67e1-47d0-84fa-c78d51682df2","pid":"131cf4bb-1971-43a2-992f-2cbb042a4184","text":"comment 4"},{"id":"386c4439-4596-47c1-99bf-cb479055fe5a","pid":"","text":"comment 5"},{"id":"5ef0816e-ea13-4a7e-8009-e67ee08ef906","pid":"386c4439-4596-47c1-99bf-cb479055fe5a","text":"comment 6"},{"id":"96b0a536-602b-4f3f-a352-020f22cdfb18","pid":"","text":"comment 7"},{"id":"d0f11e98-deea-4fd5-becb-8f406ebcae83","pid":"96b0a536-602b-4f3f-a352-020f22cdfb18","text":"comment 8"},{"id":"bad87461-3cbf-4ecb-a8c7-36876b57d652","pid":"","text":"comment 9"},{"id":"e3ee6f90-495f-4348-9c29-bd6e15ec3b39","pid":"bad87461-3cbf-4ecb-a8c7-36876b57d652","text":"comment 10"},{"id":"6a162b3f-9341-46e9-95f7-dedc6cd06868","pid":"","text":"comment 11"},{"id":"041c7c2d-0688-491e-b6cd-899eac95bd3d","pid":"","text":"comment 12"},{"id":"5acdf3ff-345b-47a5-bd66-a6687a1441b7","pid":"041c7c2d-0688-491e-b6cd-899eac95bd3d","text":"comment 13"},{"id":"aaee2ae5-7e3a-4435-a094-83bf6b77abfb","pid":"","text":"comment 14"},{"id":"6108b28c-a7af-4c5a-a38c-c22db0d34b31","pid":"aaee2ae5-7e3a-4435-a094-83bf6b77abfb","text":"comment 15"},{"id":"1736393e-95b0-4f5d-a149-50fe52c28350","pid":"","text":"comment 16"},{"id":"b646f202-17aa-4af9-b8dc-c1d8ff3529ac","pid":"1736393e-95b0-4f5d-a149-50fe52c28350","text":"comment 17"},{"id":"a8827b1d-fdbc-41c2-bdb5-38e8b308dedc","pid":"b646f202-17aa-4af9-b8dc-c1d8ff3529ac","text":"comment 18"},{"id":"76e49597-6039-4cb5-a595-556ccc2e3c12","pid":"a8827b1d-fdbc-41c2-bdb5-38e8b308dedc","text":"comment 19"},{"id":"07dc4b90-65d3-4f75-8351-457305988235","pid":"76e49597-6039-4cb5-a595-556ccc2e3c12","text":"comment 20"},{"id":"2d4e838b-82df-4ca0-bf9b-f1dfb99d6763","pid":"07dc4b90-65d3-4f75-8351-457305988235","text":"comment 21"},{"id":"617c1760-0dca-409c-af2a-c614f0530e07","pid":"","text":"comment 22"},{"id":"712c0b7e-a9e4-40fd-ab78-c39b483b1435","pid":"617c1760-0dca-409c-af2a-c614f0530e07","text":"comment 23"},{"id":"e325094c-886e-42c9-bd59-fdd7a189b384","pid":"","text":"comment 24"},{"id":"f3b8b0f9-edef-4ee6-9555-42e8595f854c","pid":"e325094c-886e-42c9-bd59-fdd7a189b384","text":"comment 25"},{"id":"6e09a231-a2ee-4aa1-a898-57695e6fe153","pid":"","text":"comment 26"},{"id":"63e629d6-c0f9-4b36-ad96-e0c47cf8bb4e","pid":"6e09a231-a2ee-4aa1-a898-57695e6fe153","text":"comment 27"},{"id":"d7b698f1-8757-46db-a6e6-5141a481b42b","pid":"","text":"comment 28"},{"id":"a7e3d522-553c-44f1-befa-047bd94f0e59","pid":"","text":"comment 29"},{"id":"fe78ce24-c2c8-4d00-b96d-8b8be9ce0f06","pid":"","text":"comment 30"},{"id":"fabdccb5-a024-4476-bd51-7d55fb685c42","pid":"","text":"comment 31"},{"id":"608d0693-6e43-46a0-9e54-107da6adb109","pid":"fabdccb5-a024-4476-bd51-7d55fb685c42","text":"comment 32"}]`

    var comments []Comment

    err := json.Unmarshal([]byte(jsondata), &comments)
    if err != nil {
        panic(err)
    }

    arranged := ArrangeComments(comments)

    arrangedjson, _ := json.MarshalIndent(arranged, "", "  ")

    fmt.Println(string(arrangedjson))
    fmt.Println("comments", len(comments), "arranged", recursiveCount(arranged))
}

func recursiveCount(arranged []*NestedComment) int {
    count := len(arranged)
    for _, item := range arranged {
        count += recursiveCount(item.Children)
    }
    return count
}

// Nesting function -------------------------------------------------------------------------

func ArrangeComments(comments []Comment) []*NestedComment {
    // Map to hold references to NestedComment by their ID
    queue := make(map[string]*NestedComment)

    // Result slice
    var result []*NestedComment

    // First, create all NestedComments and store references in the map
    for _, comment := range comments {
        nc := &NestedComment{Comment: comment}
        queue[comment.ID] = nc
    }

    // Second, loop through the map and add children to their parents
    for _, comment := range queue {
        if comment.ParentID != "" {
            parent := queue[comment.Comment.ParentID]
            if parent != nil {
                parent.Children = append(parent.Children, comment)
            }
        }
    }

    // Third, loop through the map and add all root comments to the result slice
    for _, comment := range queue {
        if comment.ParentID == "" {
            result = append(result, comment)
        }
    }

    return result
}

以上是我怎麼能改進這個嵌套邏輯以使其正常工作並提高效能的詳細內容。更多資訊請關注PHP中文網其他相關文章！