type Element interface{}func main() {  a := []int{1, 2, 3, 4, 1}  for _, i := range a {   fmt.Println(i)  }  for i := 0; i < len(a); i++ {   //fmt.Println(i)  }  fmt.Println(index0(a, 3))  fmt.Println(index0([]string{"a", "b", "c", "d", "e"}, "e"))  sort.Ints(a) //排序  fmt.Println(a)}//func index0(a Element, i interface{}) int {  if b, ok := a.([]int); ok {   if c, ok1 := i.(int); ok1 {     for indexC, v := range b {      if v == c {        return indexC      }     }   }  }  if b, ok := a.([]string); ok {   if c, ok1 := i.(string); ok1 {     for indexC, v := range b {      if v == c {        return indexC      }     }   }  }  return -1}

a=[1,2,3,4,1]for b in a :  print(b)i=0while i <len(a):  print(a[i])  i=i+1#print( sorted(a)) 方式一排序a.sort()print(a)print( a.index(3))a.count(1)