Golang
go 排序
gosliceslice
go
- 待排序元素个数 n ;
- 第 i 和第 j 个元素的比较函数 cmp ;
- 第 i 和 第 j 个元素的交换 swap ;
升序排序
intfloat64stringGolangsort.Ints()sort.Float64s()sort.Strings()
package main
import (
"fmt"
"sort"
)
func main() {
intList := []int{2, 4, 3, 5, 7, 6, 9, 8, 1, 0}
float8List := []float64{4.2, 5.9, 12.3, 10.0, 50.4, 99.9, 31.4, 27.81828, 3.14}
stringList := []string{"a", "c", "b", "d", "f", "i", "z", "x", "w", "y"}
sort.Ints(intList)
sort.Float64s(float8List)
sort.Strings(stringList)
fmt.Printf("%v\n%v\n%v\n", intList, float8List, stringList)
}
输出
[0 1 2 3 4 5 6 7 8 9]
[3.14 4.2 5.9 10 12.3 27.81828 31.4 50.4 99.9]
[a b c d f i w x y z]
降序排序
intfloat64string
gosortsort.InterfaceLen()Less()Swap(i, j)sort.Sortsort.Interface[]int[]float64[]stringIntScliceFloat64SliceStringSliceSort()sortInterfacesort.ReverseInterface.Less
package main
import (
"fmt"
"sort"
)
func main() {
intList := []int{2, 4, 3, 5, 7, 6, 9, 8, 1, 0}
float8List := []float64{4.2, 5.9, 12.3, 10.0, 50.4, 99.9, 31.4, 27.81828, 3.14}
stringList := []string{"a", "c", "b", "d", "f", "i", "z", "x", "w", "y"}
sort.Sort(sort.Reverse(sort.IntSlice(intList)))
sort.Sort(sort.Reverse(sort.Float64Slice(float8List)))
sort.Sort(sort.Reverse(sort.StringSlice(stringList)))
fmt.Printf("%v\n%v\n%v\n", intList, float8List, stringList)
}
输出
[9 8 7 6 5 4 3 2 1 0]
[99.9 50.4 31.4 27.81828 12.3 10 5.9 4.2 3.14]
[z y x w i f d c b a]
Reversesort.Reverse
package main
import (
"fmt"
"sort"
)
// 自定义的 Reverse 类型
type Reverse struct {
sort.Interface // 这样, Reverse 可以接纳任何实现了 sort.Interface (包括 Len, Less, Swap 三个方法) 的对象
}
// Reverse 只是将其中的 Inferface.Less 的顺序对调了一下
func (r Reverse) Less(i, j int) bool {
return r.Interface.Less(j, i)
}
func main() {
doubles := []float64{3.5, 4.2, 8.9, 100.98, 20.14, 79.32}
fmt.Printf("doubles is asc ? %v\n", sort.Float64sAreSorted(doubles))
//sort.Float64s(doubles) // float64 正序排序 方法1
//sort.Sort(sort.Float64Slice(doubles)) // float64 正序排序 方法2
(sort.Float64Slice(doubles)).Sort() // float64 排序方法 方法3
fmt.Println("after sort by Sort:\t", doubles)
sort.Sort(Reverse{sort.Float64Slice(doubles)}) // float64 逆序排序
fmt.Println("after sort by Reversed Sort:\t", doubles)
}
输出
doubles is asc ? false
after sort by Sort: [3.5 4.2 8.9 20.14 79.32 100.98]
after sort by Reversed Sort: [100.98 79.32 20.14 8.9 4.2 3.5]
以上只是说明了基础类型怎样进行排序。
结构体类型排序sort.Sort(slice)slicesort.Interface
第一种
[]intIntSliceIntSliceInterface
package main
import (
"fmt"
"sort"
)
type Person struct {
Name string // 姓名
Age int // 年纪
}
// 按照 Person.Age 从大到小排序
type PersonSlice []Person
func (a PersonSlice) Len() int { // 重写 Len() 方法
return len(a)
}
func (a PersonSlice) Swap(i, j int) { // 重写 Swap() 方法
a[i], a[j] = a[j], a[i]
}
func (a PersonSlice) Less(i, j int) bool { // 重写 Less() 方法, 从大到小排序
return a[j].Age < a[i].Age
}
func main() {
people := []Person{
{"zhang san", 12},
{"li si", 30},
{"wang wu", 52},
{"zhao liu", 26},
}
fmt.Println(people)
sort.Sort(PersonSlice(people)) // 按照 Age 的逆序排序
fmt.Println(people)
sort.Sort(sort.Reverse(PersonSlice(people))) // 按照 Age 的升序排序
fmt.Println(people)
}
输出
[{zhang san 12} {li si 30} {wang wu 52} {zhao liu 26}]
[{wang wu 52} {li si 30} {zhao liu 26} {zhang san 12}]
[{zhang san 12} {zhao liu 26} {li si 30} {wang wu 52}]
第二种
AgePersonSliceLenLessSwapNameAgeNameLessLessLess
package main
import (
"fmt"
"sort"
)
type Person struct {
Name string // 姓名
Age int // 年纪
}
type PersonWrapper struct {
people []Person
by func(p, q *Person) bool
}
func (pw PersonWrapper) Len() int { // 重写 Len() 方法
return len(pw.people)
}
func (pw PersonWrapper) Swap(i, j int) { // 重写 Swap() 方法
pw.people[i], pw.people[j] = pw.people[j], pw.people[i]
}
func (pw PersonWrapper) Less(i, j int) bool { // 重写 Less() 方法
return pw.by(&pw.people[i], &pw.people[j])
}
func main() {
people := []Person{
{"zhang san", 12},
{"li si", 30},
{"wang wu", 52},
{"zhao liu", 26},
}
fmt.Println(people)
sort.Sort(PersonWrapper{people, func(p, q *Person) bool {
return q.Age < p.Age // Age 递减排序
}})
fmt.Println(people)
sort.Sort(PersonWrapper{people, func(p, q *Person) bool {
return p.Name < q.Name // Name 递增排序
}})
fmt.Println(people)
}
输出
[{zhang san 12} {li si 30} {wang wu 52} {zhao liu 26}]
[{wang wu 52} {li si 30} {zhao liu 26} {zhang san 12}]
[{li si 30} {wang wu 52} {zhang san 12} {zhao liu 26}]
[]PersoncmpPersonWrapperLenLessSwapsort.Sort(pw)pwpeoplego
第三种
mainsort.SortPersonWrappermainSortPerson
package main
import (
"fmt"
"sort"
)
type Person struct {
Name string // 姓名
Age int // 年纪
}
type PersonWrapper struct {
people []Person
by func(p, q *Person) bool
}
type SortBy func(p, q *Person) bool
func (pw PersonWrapper) Len() int { // 重写 Len() 方法
return len(pw.people)
}
func (pw PersonWrapper) Swap(i, j int) { // 重写 Swap() 方法
pw.people[i], pw.people[j] = pw.people[j], pw.people[i]
}
func (pw PersonWrapper) Less(i, j int) bool { // 重写 Less() 方法
return pw.by(&pw.people[i], &pw.people[j])
}
func SortPerson(people []Person, by SortBy) { // SortPerson 方法
sort.Sort(PersonWrapper{people, by})
}
func main() {
people := []Person{
{"zhang san", 12},
{"li si", 30},
{"wang wu", 52},
{"zhao liu", 26},
}
fmt.Println(people)
sort.Sort(PersonWrapper{people, func(p, q *Person) bool {
return q.Age < p.Age // Age 递减排序
}})
fmt.Println(people)
SortPerson(people, func(p, q *Person) bool {
return p.Name < q.Name // Name 递增排序
})
fmt.Println(people)
}
输出
[{zhang san 12} {li si 30} {wang wu 52} {zhao liu 26}]
[{wang wu 52} {li si 30} {zhao liu 26} {zhang san 12}]
[{li si 30} {wang wu 52} {zhang san 12} {zhao liu 26}]
SortPerson[]Personcmp
第四种
其实是另外一种实现思路,可以说是方法一、方法二的变体。
package main
import (
"fmt"
"sort"
)
type Person struct {
Name string
Weight int
}
type PersonSlice []Person
func (s PersonSlice) Len() int { return len(s) }
func (s PersonSlice) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
type ByName struct{ PersonSlice } // 将 PersonSlice 包装起来到 ByName 中
func (s ByName) Less(i, j int) bool { return s.PersonSlice[i].Name < s.PersonSlice[j].Name } // 将 Less 绑定到 ByName 上
type ByWeight struct{ PersonSlice } // 将 PersonSlice 包装起来到 ByWeight 中
func (s ByWeight) Less(i, j int) bool { return s.PersonSlice[i].Weight < s.PersonSlice[j].Weight } // 将 Less 绑定到 ByWeight 上
func main() {
s := []Person{
{"apple", 12},
{"pear", 20},
{"banana", 50},
{"orange", 87},
{"hello", 34},
{"world", 43},
}
sort.Sort(ByWeight{s})
fmt.Println("People by weight:")
printPeople(s)
sort.Sort(ByName{s})
fmt.Println("\nPeople by name:")
printPeople(s)
}
func printPeople(s []Person) {
for _, o := range s {
fmt.Printf("%-8s (%v)\n", o.Name, o.Weight)
}
}
输出
People by weight:
apple (12)
pear (20)
hello (34)
world (43)
banana (50)
orange (87)
People by name:
apple (12)
banana (50)
hello (34)
orange (87)
pear (20)
world (43)
ByXXX