Go array and slice, []byte to string[easy to understand]

Hello everyone , I meet you again , I'm your friend, Quan Jun .

Array ： A fixed length sequence of the same data type Definition of array ：var a [len]int , such as var a[5]int Length is part of the array type , therefore ,var a [5]int and var a [10]int It's a different type

func Array() {
	// Initialization of an array 
	var age0 [5]int = [5]int{1,2,3}
	var age1 = [5]int{1,2,3,4,5}
	var age2 = [...]int{1,2,3,4,5,6}
	var str = [5]string{3:"hello world",4:"john"} // Specify the third and fourth elements of the array 
	fmt.Println(age0)
	fmt.Println(age1)
	fmt.Println(age2)
	fmt.Println(str)
}
func DemiArray() {
	// Multidimensional arrays    Define a two-dimensional array with three rows and four columns 
	var  a [3][4]int = [...][4]int{
  
  {1,2,3,4},{5,6,7,8},{9,10,11,12}}
	for _,v:= range a{
		for _,v1 := range v{
			fmt.Printf("%d\t",v1)
		}
		fmt.Printf("\n")
	}
}
func main() {
	 Array()
	 DemiArray()
}

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section ： A slice is a reference to an array , So slices are of reference type The length of the slice is variable , So the slice is a mutable array Slices are traversed in the same way as arrays , It can be used len() Find the length cap We can work out slice Maximum capacity of ,0 <= len(slice) <= cap(array), among array yes slice Array of references Definition of slice ：var Variable name [] type , such as var str []string var arr []int

func silce() {
	// Define an array and cut slices from the array 
	var a = [10]int{1,2,3,4}
	b := a[1:5]
	fmt.Println(b)
	// Defining slices , And use make Function initialization 
	var s = []int
	s = make([]int,5)
	s[0] = 1
	fmt.Println(s)
	// One slice plus another slice 
	var c = []int{1,2,3}
	var d = []int{4,5,6,7}
	c = append(c,d...) // section append section 
	fmt.Println(c)
	// A copy of the slice , Built in functions copy
	s1 :=[]int{1,2,3,4,5}
	s2 := make([]int,10)
	copy(s2,s1)
	fmt.Printf("s2:%d\n",s2)
}

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[]byte Interturn string s1 := “hello,word” s2 :=[]byte(s1) //string turn []byte s1 = string(s2) //[]byte turn string

func modifystring () {
	//slice And string The relationship between 
	/*string It is immutable in itself , So change string String in , The following operations are required */
	str := "hello world"
	s := []byte(str)
	s[0] = '0'
	str = string(s)
	fmt.Println(str)
	// But if the string is in Chinese, it can be converted to byte The array of type is wrong , Should use the 
	s1 := " I love you! , China "
	s2 := []rune(s1)
	s2[0] = ' you '
	s1 = string(s2)
	fmt.Println(s1)
}

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use slice Non recursive realization of Fibonacci sequence

func fibo(n int){
	// use slice Non recursive implementation Fibonacci The sequence 
	var a [] int64
	a = make([]int64,n)
	a[0] = 1
	a[1] = 1
	for i := 2; i < n; i++{
		a[i] = a[i-1] +a[i-2]
	} 
	for _,v := range a{
		fmt.Println(v,)
	}
}

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