golang中按照结构体的某个字段排序实例代码

来源：jb51　　时间：2022/5/30 9:33:54　　对本文有异议

概述

golang的sort包默认支持int, float64, string的从小大到排序：

int -> Ints(x []int)
float64 -> Float64s(x []float64)
string -> Strings(x []string)

同时它还提供了自定义的排序接口Interface，此接口保护三个方法。

type Interface interface {
    // Len is the number of elements in the collection.
    Len() int
    // Less reports whether the element with
    // index i should sort before the element with index j.
    Less(i, j int) bool
    // Swap swaps the elements with indexes i and j.
    Swap(i, j int)
}

golang默认提供了三个类型，他们都实现了Interface：
Float64Slice
IntSlice
StringSlice

从大到小排序

方法1：先使用提供的从大到小排序，再翻转

arr := []float64{0.1, 0.5, 0.8, 0.4, 0.2}
 
sort.Sort(sort.Reverse(sort.Float64Slice(arr)))
fmt.Println(arr) // [0.8 0.5 0.4 0.2 0.1]

方法二：自定义类型实现

type Float64SliceDecrement []float64
func (s Float64SliceDecrement) Len() int { return len(s) }
func (s Float64SliceDecrement) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s Float64SliceDecrement) Less(i, j int) bool { return s[i] > s[j] }
func main() {
	arr := []float64{0.1, 0.5, 0.8, 0.4, 0.2}
	
	sort.Sort(Float64SliceDecrement(arr))
	fmt.Println(arr) // [0.8 0.5 0.4 0.2 0.1]
}

按照结构体的某个字段排序

按年纪从大到小排序

type Persons struct {
	Age int
	Height int
}
 
type PersonsSliceDecrement []Persons
func (s PersonsSliceDecrement) Len() int { return len(s) }
func (s PersonsSliceDecrement) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s PersonsSliceDecrement) Less(i, j int) bool { return s[i].Age > s[j].Age }
func main() {
	arr1 := []Persons{
		Persons{10, 12},
		Persons{20, 12},
		Persons{9, 12},
		Persons{10, 12},
		Persons{11, 12},
	}
	sort.Sort(PersonsSliceDecrement(arr1))
	fmt.Println(arr1)
}

打印

[{20 12} {11 12} {10 12} {10 12} {9 12}]

按年纪从大到小，如果年纪相等的，按身高从小到到

type Persons struct {
	Age int
	Height int
}
 
type PersonsSliceDecrement []Persons
func (s PersonsSliceDecrement) Len() int { return len(s) }
func (s PersonsSliceDecrement) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s PersonsSliceDecrement) Less(i, j int) bool {
	if s[i].Age > s[j].Age {
		return true
	}
	if s[i].Age == s[j].Age && s[i].Height < s[j].Height {
		return true
	}
	return false
}
 
func main() {
	arr1 := []Persons{
		Persons{10, 120},
		Persons{20, 12},
		Persons{10, 110},
		Persons{10, 11},
		Persons{10, 100},
	}
	sort.Sort(PersonsSliceDecrement(arr1))
	fmt.Println(arr1)
}

打印

[{20 12} {10 11} {10 100} {10 110} {10 120}]

使用 sort.Stable 进行稳定排序

sort.Sort 并不保证排序的稳定性。如果有需要, 可以使用 sort.Stable ，用法就是将sort.Sort 替换为 sort.Stable

附：go根据结构体中任意字段进行排序

附：根据结构体中任意字段进行排序

Sort()

Reverse()

Less(i,j int) bool

Len() int

Swap(i,j int)

package main
 
import (
	"fmt"
	"sort"
)
 
type Student struct {
	Number   string
	Name     string
	Age      int
	IsWalker bool
	Weight   float32
}
 
type ByNumber []*Student
 
func (this ByNumber)Len() int  {
	return len(this)
}
 
func (this ByNumber)Less(i,j int) bool  {
	return this[i].Number<this[j].Number
}
 
func (this ByNumber)Swap(i,j int) {
	this[i],this[j] = this[j],this[i]
}
 
func (this ByNumber) String() string {
	const  format = "| %v |\t%v |\t%v |\t %v |\t %v |\t%v   |\n"
    fmt.Println("\t\t\t\t\t学生信息表")
    fmt.Println(" 序号\t学号 \t姓名\t   年龄\t  体重\t   是否走读")
	for k,v:=range this{
		fmt.Printf(format,k+1,v.Number,v.Name,v.Age,v.Weight,v.IsWalker)
	}
	return ""
}
 
func main1() {
	sts:=[]*Student{
		&Student{Number: "003",Name: "张三"},
		&Student{Number: "004",Name: "张四"},
		&Student{Number: "001",Name: "张一"},
		&Student{Number: "002",Name: "张二"},
		&Student{Number: "000",Name: "张零"},
	}
	b:=ByNumber(sts)
	sort.Sort(b)
	fmt.Println(b)
	fmt.Println("反转")
	sort.Sort(sort.Reverse(b))  //反转的用法
	fmt.Println(b)
 
 
	//为结构体内的每一个字段都绑定一个排序的外壳，这种操作显然不是很聪明
    //这时候使用组合来解决这个问题
}
 
 
type customSort struct {
	s []*Student
	less func(i,j *Student)  bool
}
 
func (this *customSort)Len() int {
	return len(this.s)
}
 
func (this *customSort)Swap(i,j int) {
	this.s[i],this.s[j] = this.s[j],this.s[i]
}
 
func (this *customSort)Less(i,j int) bool {
	return this.less(this.s[i],this.s[j])
}
 
func main()  {
	sts:=[]*Student{
		&Student{Number: "003",Name: "张三"},
		&Student{Number: "004",Name: "张四"},
		&Student{Number: "001",Name: "张一"},
		&Student{Number: "000",Name: "张二"},
		&Student{Number: "002",Name: "张二"},
	}
 
	c:=&customSort{
		s: sts,
		less: func(i, j *Student) bool {
			if i.Number != j.Number {    //可以指定多种排序规则
				return i.Number>j.Number
			}
			if i.Name!=j.Name{
				return i.Name<j.Name
			}
			return false
		},
	}
 
	/*
	package sort
	// A type, typically a collection, that satisfies sort.Interface can be
	// sorted by the routines in this package. The methods require that the
	// elements of the collection be enumerated by an integer index.
	type Interface interface {
		// Len is the number of elements in the collection.
		Len() int
		// Less reports whether the element with
		// index i should sort before the element with index j.
		Less(i, j int) bool
		// Swap swaps the elements with indexes i and j.
		Swap(i, j int)
	}
*/
	sort.Sort(c) //Sort方法中不只能放slice类型，还可以放结构体类型,只要改类型 实现 Sort接口
	fmt.Println(ByNumber(sts)) //单纯的使用一下ByNumber中重写是String()方法
}