php小编鱼仔，你可能在编写代码时遇到了嵌套逻辑的问题，导致代码无法正常工作或性能较低。要改进这个问题，有几个关键点需要考虑。首先，你可以重新审视你的逻辑结构，看看是否可以简化或重构代码，以减少嵌套层级。其次，你可以考虑使用适当的数据结构和算法来优化你的代码。另外，确保你的代码没有重复的计算或冗余的操作，以提高性能。最后，进行适当的测试和调试，以确保你的代码在各种情况下都能正常工作。通过这些方法，你可以改进嵌套逻辑并提高代码的性能。
问题内容
我有一个包含评论的数据库，每个评论都有一个 ID 和一个父 ID。目标只是以高效的方式将带有父 ID 的每个评论放在其父评论下。
我最初使用递归函数在 arranged 数组中搜索父注释，但性能很糟糕。我重构为使用指针来跟踪父母，这几乎完美地工作，但似乎最后要处理的评论总是被排除在输出之外。
在下面的示例中，“comment 1”应该是“comment 11”的子级，但它根本不包含在输出中。
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
}
登录后复制
<小时/>
更新；这让我更接近，但无法嵌套一些更深层次的嵌套评论。奇怪的是，它每次运行时都会产生不同的输出：
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
}
登录后复制
<小时/>
更新；我快速编写了一个 JavaScript 实现，它可以在给定相同示例数据的情况下生成正确的结果，但我无法弄清楚为什么此 JS 代码可以工作而 Go 代码不起作用。
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))
登录后复制
<小时/>
可运行的 Go 示例：https://gist.github.com/dlford/9e66069cfc7fb9afc649c5e3dc650083
可运行的 JS 示例：https://gist.github.com/dlford/f6f4a383a99f65659895ed51d1a4b651
Go 代码输出（参见底部的计数）：https://gist.github.com/dlford/302c4db939c21d15132848368caa01ec
JS 代码输出（参见底部的计数）：https://gist.github.com/dlford/60ab49d0466c957c7745059022e27e09
解决方法
问题是 NestedComment 中的 Children 也需要存储为指针。
工作示例：
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
}
登录后复制
以上是我怎样才能改进这个嵌套逻辑以使其正常工作并提高性能的详细内容。更多信息请关注PHP中文网其他相关文章！
