golang sort包 排序

[]float64:

ls := sort.Float64Slice{
    1.1,
    4.4,
    5.5,
    3.3,
    2.2,
}
fmt.Println(ls)  //[1.1 4.4 5.5 3.3 2.2]
sort.Float64s(ls)
fmt.Println(ls)   //[1.1 2.2 3.3 4.4 5.5]

[]int:

ls := sort.IntSlice{
    1,
    4,
    5,
    3,
    2,
}
fmt.Println(ls)  //[1 4 5 3 2]
sort.Ints(ls)
fmt.Println(ls)  //[1 2 3 4 5]

string:

//字符串排序，现比较高位，相同的再比较低位
ls := sort.StringSlice{
    "100",
    "42",
    "41",
    "3",
    "2",
}
fmt.Println(ls)  //[100 42 41 3 2]
sort.Strings(ls)
fmt.Println(ls)  //[100 2 3 41 42]


//字符串排序，现比较高位，相同的再比较低位
ls := sort.StringSlice{
    "d",
    "ac",
    "c",
    "ab",
    "e",
}
fmt.Println(ls)  //[d ac c ab e]
sort.Strings(ls)
fmt.Println(ls)  //[ab ac c d e]



//汉字排序，依次比较byte大小
ls := sort.StringSlice{
    "啊",
    "博",
    "次",
    "得",
    "饿",
    "周",
}
fmt.Println(ls)  //[啊 博 次 得 饿 周]
sort.Strings(ls)
fmt.Println(ls)  //[博 周 啊 得 次 饿]

for _, v := range ls{
    fmt.Println(v, []byte(v))
}

//博 [229 141 154]
//周 [229 145 168]
//啊 [229 149 138]
//得 [229 190 151]
//次 [230 172 161]
//饿 [233 165 191]

复杂结构：

1. [][]int :

type testSlice [][]int

func (l testSlice) Len() int            { return len(l) }
func (l testSlice) Swap(i, j int)      { l[i], l[j] = l[j], l[i] }
func (l testSlice) Less(i, j int) bool { return l[i][1] < l[j][1] }

func main() {
    ls := testSlice{
        {1,4},
        {9,3},
        {7,5},
    }

    fmt.Println(ls)  //[[1 4] [9 3] [7 5]]
    sort.Sort(ls)
    fmt.Println(ls)  //[[9 3] [1 4] [7 5]]
}

2. []map[string]int     [{"k":0},{"k1":1},{"k2":2] :

type testSlice []map[string]float64

func (l testSlice) Len() int            { return len(l) }
func (l testSlice) Swap(i, j int)      { l[i], l[j] = l[j], l[i] }
func (l testSlice) Less(i, j int) bool { return l[i]["a"] < l[j]["a"] } //按照"a"对应的值排序

func main() {
    ls := testSlice{
        {"a":4, "b":12},
        {"a":3, "b":11},
        {"a":5, "b":10},
    }


    fmt.Println(ls)  //[map[a:4 b:12] map[a:3 b:11] map[a:5 b:10]]
    sort.Sort(ls)
    fmt.Println(ls)  //[map[a:3 b:11] map[a:4 b:12] map[a:5 b:10]]
}

3. []struct :

type People struct {
    Name string `json:"name"`
    Age int `json:"age"`
}

type testSlice []People

func (l testSlice) Len() int            { return len(l) }
func (l testSlice) Swap(i, j int)      { l[i], l[j] = l[j], l[i] }
func (l testSlice) Less(i, j int) bool { return l[i].Age < l[j].Age }

func main() {
    ls := testSlice{
        {Name:"n1", Age:12},
        {Name:"n2", Age:11},
        {Name:"n3", Age:10},
    }


    fmt.Println(ls)  //[{n1 12} {n2 11} {n3 10}]
    sort.Sort(ls)
    fmt.Println(ls)  //[{n3 10} {n2 11} {n1 12}]
}

4. 复杂的时候,按float64类型排序:

type People struct {
    Name string `json:"name"`
    Age float64 `json:"age"`
}
func isNaN(f float64) bool {
    return f != f
}
type testSlice []People

func (l testSlice) Len() int            { return len(l) }
func (l testSlice) Swap(i, j int)      { l[i], l[j] = l[j], l[i] }
func (l testSlice) Less(i, j int) bool { return l[i].Age < l[j].Age || isNaN(l[i].Age) && !isNaN(l[j].Age)}

func main() {
    ls := testSlice{
        {Name:"n1", Age:12.12},
        {Name:"n2", Age:11.11},
        {Name:"n3", Age:10.10},
    }


    fmt.Println(ls)  //[{n1 12.12} {n2 11.11} {n3 10.1}]
    sort.Sort(ls)
    fmt.Println(ls)  //[{n3 10.1} {n2 11.11} {n1 12.12}]
}