golang 之 slice

   
 package arraryList
    
    import "fmt"
    
    type ArraryList struct {
    	Slice []interface{}
    }
    
    func test() {
    	//s := make([]interface{}, 10)
    	s := make([]interface{}, 0, 10)
    	for i := 0; i < cap(s); i++ {
    		s = append(s, i)
    	}
    	fmt.Println("the origin s and cap:", s, cap(s))
    	/**
    		slice s的增删查改
         */
    	arraryList := &ArraryList{}
    	s = arraryList.Add(s, 100, 6)
    	arraryList.AddLast(&s, 101)
    	fmt.Println("add s and cap:", s, cap(s))
    
    	s = arraryList.Edit(s, 100, 5)
    	fmt.Println("edit s and cap:", s, cap(s))
    
    	s = arraryList.Remove(s, 5)
    	fmt.Println("delete s and cap:", s, cap(s))
    
    	value := arraryList.Get(s, 5)
    	fmt.Printf("get s[%d]'s value:%v\n", 5, value)
    
    	s1 := s
    
    	//使用字面量赋值
    	s = []interface{}{10, 11, 12, 13, 14, 15, 16}
    
    	//赋值之后不影响之前的s
    	fmt.Println("after reset s, s1 and cap:", s1, cap(s1))
    
    	s2 := s1[1:]
    	s3 := s[1:]
    	fmt.Println(" cap(s2) and cap(s3)", cap(s2), cap(s3))
    }
    
    func (this *ArraryList) Add(s []interface{}, elem interface{}, index int) ([]interface{}) {
    	ss := make([]interface{}, cap(s)+1)
    	copy(ss, s[:index])
    	ss[index] = elem
    	copy(ss[index+1:], s[index:])
    	return ss
    }
    
    func (this *ArraryList) AddLast(s *[]interface{}, elem interface{}) {
    	*s = append(*s, elem)
    }
    
    func (this *ArraryList) Edit(s []interface{}, elem interface{}, index int) ([]interface{}) {
    	s[index] = elem
    	return s
    }
    
    func (this *ArraryList) Remove(s []interface{}, index int) ([]interface{}) {
    	ss := append(s[:index], s[index+1:]...)
    	return ss
    }
    
    func (this *ArraryList) Get(s []interface{}, index int) (interface{}) {
    	return s[index]
    }
    
    func (this *ArraryList) GetFirst(s []interface{}) (interface{}) {
    	return this.Get(s, 0)
    }
    
    func (this *ArraryList) GetLast(s []interface{}) (interface{}) {
    	return this.Get(s, len(s)-1)
    }

1. slice 的区间向右扩展 cap eg：s2,s3
2. cap 增长在 1024 以内 2 倍,大于则为 1.25 倍增长
3. 修改字面变量不会改变原来 slice 的值 eg:s1
4. append 修改需要传入指针 否则 appen 无效 eg: AddLast()
5. cap 值很大的情况不适合用 slice
6. slice 是数组的 view