A commonly used container
1 Array
definition method
var array name [size] type
example
package main
import "fmt"//导入包必须使用，否则编译报错
func main() {//g语言中的 ‘{’ 不能独占一行
var arr[4]int;
fmt.Println("arr:",arr)
var arr2 = [4]int{1,2,3,4}
fmt.Println("arr2:",arr2)
fmt.Println("arr == arr2",arr == arr2)//可以直接比较
var arr3 = [...]int{1,3,5}//自动推导大小
fmt.Println("arr3:",arr3)
arr4 := [3][4]int{
{2:10} ,{4, 5, 6, 7}}
fmt.Println("arr4:",arr4)
}
As a result,
array initialization is very flexible.
2 slice, the
bottom layer is the array
example
package main
import "fmt"//导入包必须使用，否则编译报错
func main() {//g语言中的 ‘{’ 不能独占一行
//make创建
slice1 := make([]int,5,10)//make(类型，长度，容量)
fmt.Println("")
fmt.Println("slice1:",slice1)
//自动推导并初始化
slice2 := []int{1,2,3,4}//起始位，结束位，容量
fmt.Println("slice2:",slice2)
//切片截取
var arr = [6]int{1,2,3,4,5,6}
fmt.Println("arr:",arr)
slice3 := arr[3:]//数组下标3之后的
fmt.Println("slice3:",slice3)
slice4 := arr[:3]//数组下标3之前的
fmt.Println("slice4:",slice4)
slice5 := arr[3:5]//数组下标3和5之间的
fmt.Println("slice5:",slice5)
slice5[1]=100
fmt.Println("arr:",arr)//数组也会改变
}
Result
3 The map
is similar to other languages that you are familiar with.
Example
package main
import "fmt"//导入包必须使用，否则编译报错
func main() {//g语言中的 ‘{’ 不能独占一行
//make创建
map1 := make(map[int]string)//创建一个map，key是int，value是string
map1[1]="111"
fmt.Println("map1:",map1)
for key,value := range map1{
fmt.Printf("key = %d,value = %s\n",key,value)
}
//自动推导
//map2 := map[int]string
}
result
Two containers as parameters
package main
import "fmt"//导入包必须使用，否则编译报错
func ChangeArr(arr[4]int){
arr[1]= 10
fmt.Println("ChangeArr arr:",arr)
}
func ChangeArr1(arr*[4]int){
arr[1]= 10
fmt.Println("ChangeArr1 arr:",arr)
}
func ChangeSlice(sli[]int){
sli[1]= 10
fmt.Println("ChangeSlice sli:",sli)
}
func ChangeMap(mmap map[int]string){
mmap[1] = "99"
fmt.Println("ChangeMap mmap:",mmap)
}
func main() {//g语言中的 ‘{’ 不能独占一行
arr := [4]int{1,2,3,4}
ChangeArr(arr)
fmt.Println("main arr:",arr)
ChangeArr1(&arr)
fmt.Println("main arr:",arr)
slice :=[]int{1,2,3,4}
ChangeSlice(slice)
fmt.Println("main slice:",slice)
mmap :=make(map[int]string)
mmap[0] = "00"
mmap[1] = "11"
mmap[2] = "22"
mmap[3] = "33"
fmt.Println("main mmap:",mmap)
ChangeMap(mmap)
fmt.Println("main mmap:",mmap)
}
The result
map and slice are passed by reference, array is passed by value
Three structure
package main
import "fmt"//导入包必须使用，否则编译报错
type Student struct{
id int
name string
}
func ChangeStr(stu Student){
stu.id = 11
}
func main() {//g语言中的 ‘{’ 不能独占一行
stu := Student{01,"张飞"}
fmt.Println(stu)
stu.id = 15
fmt.Println(stu)
var p1* Student
p1 = &stu
p1.id = 20
fmt.Println(stu)
(*p1).id = 25 //通过指针操作*p1和p1等价
fmt.Println(stu)
p2 := new (Student)
p2.id = 10;
p2.name = "小明"
fmt.Println(p2)
fmt.Println("p1 == p2",p1==p2)
ChangeStr(*p2)
fmt.Println("main",p2)
}
The result
structure is passed by value.
At the same time, let me first mention that a structure in a package, a member in a structure, a method, if the first letter is lowercase, it is equivalent to a private variable in C++, and other packages cannot be used.