golang基础-排序、二分查找、map、map排序反转

排序

package mainimport(    "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)}/*数组是值类型，如果要改变值，需要传切片进去，去改变*/func testInSort(){    var a = [...]int{1,3,5,-5,0,-4}    //需要传递切片进去才能排序    sort.Ints(a[:])    fmt.Println(a)}

输出如下：

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>

二分查找

ort.SearchInts(a []int, b int) 从数组a中查找b，前提是a必须有序
sort.SearchFloats(a []float64, b float64) 从数组a中查找b，前提是a必须有序
sort.SearchStrings(a []string, b string) 从数组a中查找b，前提是a必须有序

package mainimport(    "fmt"    "sort")func main() {    testSearchIn()}//从数组a中查找b，前提是a必须有序func testSearchIn(){    var a = [...] int {1,8,38,2,348,484,-6}    //没有排序直接进行查找    index:= sort.SearchInts(a[:],2)    //输出1是错误的，因为没有排序    fmt.Println(index)    //进行排序操作    sort.Ints(a[:])    fmt.Println(a)    //传切片过去    index= sort.SearchInts(a[:],2)    fmt.Println(index)}

输出如下：

PS E:\golang\go_pro\src\safly> go run demo.go1[-6 1 2 8 38 348 484]2PS E:\golang\go_pro\src\safly>

map

map创建方式

package mainimport(    "fmt")func main() {    testMap()    testMoreMap()}//map嵌套func testMoreMap(){    a:= make(map[string]map[string]string,100)    //value是map，使用时候需要为其开辟空间    a["k1"] = make(map[string]string)    a["k1"]["k1k1"]= "aaa"    fmt.Println(a)}//创建map的2种方式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)}

输出如下：

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

map循环遍历

package mainimport(    "fmt")func main() {    testMap3()    fmt.Println("---------------")    testMap4()    testMap5()}/*切片里面是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)}/*循环遍历*/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)        }    }    //删除    fmt.Println("-------删除前后-------")    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"]    //输出false    fmt.Println(ok)    if !ok {        a["zhangsan"] = make(map[string]string)    }    a["zhangsan"]["pass"] = "123"    return}

输出如下：

PS E:\golang\go_pro\src\safly> go run demo.gofalsemap[zhangsan:map[pass:123]]---------------k1k2 abck3 bcdk2k4 efgk5 hij-------删除前后-------k2k4 efgk5 hij[map[10:10] map[] map[] map[] map[]]PS E:\golang\go_pro\src\safly>

排序、反转

package mainimport(    "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    //定义一个切片    var b []int    //说明map是无序的    for k,v := range a{        fmt.Println(k,v)        b = append(b,v)    }    sort.Ints(b)    fmt.Println("----------对map的值进行排序（放到切片里面）-----------")    for k,v:= range b{        fmt.Println(k,v)    }}

输出如下：

PS E:\golang\go_pro\src\safly> go run demo.go1 102 113 124 13----------对map的值进行排序（放到切片里面）-----------0 101 112 123 13--------b 2a 1PS E:\golang\go_pro\src\safly>