排序

package main

import(
    "fmt"
    "sort"
)

func main() {
    testInSort()
    testString()
    testFloat()
}

func testFloat(){
    var a = [...]float64{12.5,455.677,236.77,-234.66,0,5.99}
    sort.Float64s(a[:])
    fmt.Println(a)
}

func testString(){
    var a = [...]string{"wefD","wefghn"
 
,"thGw","wGGef","sfsf"}
    sort.Strings(a[:])
    fmt.Println(a)
}

/*陣列是值型別，如果要改變值，需要傳切片進去，去改變*/
func testInSort(){

    var a = [...]int{1,3,5,-5,0,-4}
    //需要傳遞切片進去才能排序
    sort.Ints(a[:])
    fmt.Println(a)


}

輸出如下：

PS E:\golang\go_pro\src\safly> go run demo.go
[-5 -4 0 1 3 5]
[sfsf thGw wGGef wefD wefghn]
 

[-234.66 0 5.99 12.5 236.77 455.677]
PS E:\golang\go_pro\src\safly>

二分查詢

ort.SearchInts(a []int, b int) 從陣列a中查詢b，前提是a必須有序
sort.SearchFloats(a []float64, b float64) 從陣列a中查詢b，前提是a必須有序
sort.SearchStrings(a []string, b string) 從陣列a中查詢b，前提是a必須有序

package main

import(
    "fmt"
    "sort"
)

func main() {
    testSearchIn()

}
//從陣列a中查詢b，前提是a必須有序
 

func testSearchIn(){
    var a = [...] int {1,8,38,2,348,484,-6}
    //沒有排序直接進行查詢
    index:= sort.SearchInts(a[:],2)
    //輸出1是錯誤的，因為沒有排序
    fmt.Println(index)

    //進行排序操作
    sort.Ints(a[:])
    fmt.Println(a)
    //傳切片過去
    index= sort.SearchInts(a[:],2)
    fmt.Println(index)

}

輸出如下：

PS E:\golang\go_pro\src\safly> go run demo.go
1
[-6 1 2 8 38 348 484]
2
PS E:\golang\go_pro\src\safly>

map

map建立方式

package main

import(
    "fmt"
)


func main() {
    testMap()
    testMoreMap()
}

//map巢狀
func testMoreMap(){

    a:= make(map[string]map[string]string,100)
    //value是map，使用時候需要為其開闢空間
    a["k1"] = make(map[string]string)
    a["k1"]["k1k1"]= "aaa"
    fmt.Println(a)
}

//建立map的2種方式
func testMap(){
     a  := make(map[string]string,10)
    a["abc"] = "abc"
    fmt.Println(a)

    var b map[string] string = map[string]string{
        "bcd":"bcd",
    }
    fmt.Println(b)
}

輸出如下：

PS E:\golang\go_pro\src\safly> go run demo.go
map[abc:abc]
map[bcd:bcd]
map[k1:map[k1k1:aaa]]
PS E:\golang\go_pro\src\safly>

map迴圈遍歷

package main

import(
    "fmt"
)


func main() {
    testMap3()
    fmt.Println("---------------")
    testMap4()
    testMap5()
}
/*切片裡面是map*/
func testMap5() {
    var a []map[int]int
    a = make([]map[int]int, 5)

    if a[0] == nil {
        a[0] = make(map[int]int)
    }
    a[0][10] = 10
    fmt.Println(a)
}
/*迴圈遍歷*/
func testMap4(){
    a:= make(map[string]map[string]string,100)
    a["k1"] = make(map[string]string)
    a["k1"]["k2"] = "abc"
    a["k1"]["k3"] = "bcd"

    a["k2"] = make(map[string]string)
    a["k2"]["k4"] = "efg"
    a["k2"]["k5"] = "hij"

    for k,v := range a{
        fmt.Println(k)
        for k1,v1:= range v{
            fmt.Println(k1,v1)
        }
    }

    //刪除
    fmt.Println("-------刪除前後-------")
    delete(a,"k1")
    for k,v := range a{
        fmt.Println(k)
        for k1,v1:= range v{
            fmt.Println(k1,v1)
        }
    }
 }


func testMap3(){
    a := make(map[string]map[string]string,10)
    modify(a)
    fmt.Println(a)
}

func modify(a map[string]map[string]string){
    _,ok:=a["zhangsan"]
    //輸出false
    fmt.Println(ok)
    if !ok {
        a["zhangsan"] = make(map[string]string)
    }
    a["zhangsan"]["pass"] = "123"
    return
}

輸出如下：

PS E:\golang\go_pro\src\safly> go run demo.go
false
map[zhangsan:map[pass:123]]
---------------
k1
k2 abc
k3 bcd
k2
k4 efg
k5 hij
-------刪除前後-------
k2
k4 efg
k5 hij
[map[10:10] map[] map[] map[] map[]]
PS E:\golang\go_pro\src\safly>

排序、反轉

package main

import(
    "fmt"
    "sort"
)


func testMapReverse(){
    var a map[int]string 
    var b map[string] int
    a = make(map[int]string,5)
    b = make(map[string] int ,5)

    a[1] = "a"
    a[2] = "b"

    for k,v := range a{
        b[v] = k
    }
    for k,v := range b{
        fmt.Println(k,v)
    }

}
func main() {

    testMapSort()
    fmt.Println("--------")
    testMapReverse()
}

func testMapSort(){
    var a map[int]int 
    a = make(map[int]int ,8)
    a[1] = 10
    a[2] = 11
    a[3] = 12
    a[4] = 13
    //定義一個切片
    var b []int
    //說明map是無序的
    for k,v := range a{
        fmt.Println(k,v)
        b = append(b,v)
    }

    sort.Ints(b)
    fmt.Println("----------對map的值進行排序（放到切片裡面）-----------")
    for k,v:= range b{
        fmt.Println(k,v)
    }
}

輸出如下：

PS E:\golang\go_pro\src\safly> go run demo.go
1 10
2 11
3 12
4 13
----------對map的值進行排序（放到切片裡面）-----------
0 10
1 11
2 12
3 13
--------
b 2
a 1
PS E:\golang\go_pro\src\safly>