介绍

Golang 自身不带数组去重函数, 以下是自己实现的去重代码片段.

实现

去重分为有序和无序两种类型.

• 对数据顺序没有要求的情况下,先进行排序,再遍历去重.
• 要求数据顺序按原顺序排列的情况下,使用map留存已遍历的数据并用于校验即将访问到的数据.

基本类型

无序

func IntReduce(data []int) []int {
	sort.Ints(data)
	var lastData int
	for key := 0; key < len(data); key++ {
		val := data[key]
		if key == 0 {
			lastData = val
			continue
		}

		if val == lastData {
			data = append(data[:key], data[key+1:]...)
			key--
		}
		lastData = val
	}
	return data
}

有序

func IntReduceOrder(data []int) []int {
	hm := make(map[int]int, len(data))
	for key := 0; key < len(data); key++ {
		val := data[key]

		if _, ok := hm[val]; ok {
			data = append(data[:key], data[key+1:]...)
			key--
			continue
		}

		hm[val] = key
	}
	return data
}

运行结果

data = []int{1, 2, 3, 4, 5, 6, 8, 8, 9, 9, 7, 7, 1}

无序方案结果
[1 2 3 4 5 6 7 8 9]

有序方案结果
[1 2 3 4 5 6 8 9 7]

引用类型

样例数据结构

type UserBase struct {
	Id       int    `json:"id"`
	Username string `bson:"username"`
	Age      int    `json:"age"`
	City     string `json:"city"`
	Address  string `json:"address"`
	Country  string `json:"country"`
}

type UserBases []UserBase

// 实现Golang的排序接口Sort
func (x UserBases) Len() int           { return len(x) }
func (x UserBases) Less(i, j int) bool { return x[i].Id < x[j].Id }
func (x UserBases) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }

无序

func UserBasesReduce(data UserBases) UserBases {
	sort.Sort(data)
	var lastData int
	for key := 0; key < len(data); key++ {
		userBase := data[key]
		if key == 0 {
			lastData = userBase.Id
			continue
		}

		if userBase.Id == lastData {
			data = append(data[:key], data[key+1:]...)
			key--
		}
		lastData = userBase.Id
	}
	return data
}

有序

func UserBasesReduceOrder(data UserBases) UserBases {
	hm := make(map[int]int, len(data))
	for key := 0; key < len(data); key++ {
		val := data[key]

		if _, ok := hm[val.Id]; ok {
			data = append(data[:key], data[key+1:]...)
			key--
			continue
		}

		hm[val.Id] = key
	}
	return data
}

运行结果

var data = []UserBase{
		{Id: 1,Username: "First",Age: 10},
		{Id: 5,Username: "Fifth",Age: 50},
		{Id: 3,Username: "Third01",Age: 30},
		{Id: 3,Username: "Third02",Age: 30},
		{Id: 2,Username: "Second",Age: 20},
		{Id: 4,Username: "Fourth",Age: 40},
		{Id: 2,Username: "Second",Age: 20},
		{Id: 4,Username: "Fourth",Age: 40},
	}

无序方案结果
{Id:1 Username:First Age:10 City: Address: Country:}
{Id:2 Username:Second Age:20 City: Address: Country:}
{Id:3 Username:Third01 Age:30 City: Address: Country:}
{Id:4 Username:Fourth Age:40 City: Address: Country:}
{Id:5 Username:Fifth Age:50 City: Address: Country:}

有序方案结果
{Id:1 Username:First Age:10 City: Address: Country:}
{Id:5 Username:Fifth Age:50 City: Address: Country:}
{Id:3 Username:Third01 Age:30 City: Address: Country:}
{Id:2 Username:Second Age:20 City: Address: Country:}
{Id:4 Username:Fourth Age:40 City: Address: Country:}

原文地址：http://www.cnblogs.com/ryanrew/p/16858449.html