切片的其他妙用

b := a[:0]for _, x := range a {	if f(x) {		b = append(b, x)	}}

for i := len(b); i < len(a); i++ {	a[i] = nil // or the zero value of T}

for i := len(a)/2-1; i >= 0; i-- {	opp := len(a)-1-i	a[i], a[opp] = a[opp], a[i]}

for left, right := 0, len(a)-1; left < right; left, right = left+1, right-1 {	a[left], a[right] = a[right], a[left]}

for i := len(a) - 1; i > 0; i-- {    j := rand.Intn(i + 1)    a[i], a[j] = a[j], a[i]}

actions := []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}batchSize := 3batches := make([][]int, 0, (len(actions) + batchSize - 1) / batchSize)
for batchSize < len(actions) {    actions, batches = actions[batchSize:], append(batches, actions[0:batchSize:batchSize])}batches = append(batches, actions)

[[0 1 2] [3 4 5] [6 7 8] [9]]

import "sort"
in := []int{3,2,1,4,3,2,1,4,1} // any item can be sortedsort.Ints(in)j := 0for i := 1; i < len(in); i++ {	if in[j] == in[i] {		continue	}	j++	// preserve the original data	// in[i], in[j] = in[j], in[i]	// only set what is required	in[j] = in[i]}result := in[:j+1]fmt.Println(result) // [1 2 3 4]

// moveToFront moves needle to the front of haystack, in place if possible.func moveToFront(needle string, haystack []string) []string {	if len(haystack) != 0 && haystack[0] == needle {		return haystack	}	prev := needle	for i, elem := range haystack {		switch {		case i == 0:			haystack[0] = needle			prev = elem		case elem == needle:			haystack[i] = prev			return haystack		default:			haystack[i] = prev			prev = elem		}	}	return append(haystack, prev)}
haystack := []string{"a", "b", "c", "d", "e"} // [a b c d e]haystack = moveToFront("c", haystack)         // [c a b d e]haystack = moveToFront("f", haystack)         // [f c a b d e]

func slidingWindow(size int, input []int) [][]int {	// returns the input slice as the first element	if len(input) <= size {		return [][]int{input}	}
	// allocate slice at the precise size we need	r := make([][]int, 0, len(input)-size+1)
	for i, j := 0, size; j <= len(input); i, j = i+1, j+1 {		r = append(r, input[i:j])	}
	return r}