feat: add Intersection, Union, Without func for slice/slice.go

slice/slice.go

@@ -379,22 +379,28 @@ func Unique(slice interface{}) interface{} {
 		return slice
 	}
 
-	var res []interface{}
+	var temp []interface{}
+	len := 0
 	for i := 0; i < sv.Len(); i++ {
 		v := sv.Index(i).Interface()
-		flag := true
-		for j := range res {
-			if v == res[j] {
-				flag = false
+		skip := true
+		for j := range temp {
+			if v == temp[j] {
+				skip = false
 				break
 			}
 		}
-		if flag {
-			res = append(res, v)
+		if skip {
+			temp = append(temp, v)
+			len++
 		}
 	}
 
-	return res
+	res := reflect.MakeSlice(sv.Type(), len, len)
+	for i := 0; i < len; i++ {
+		res.Index(i).Set(reflect.ValueOf(temp[i]))
+	}
+	return res.Interface()
 
 	// if use map filter, the result slice element order is random, not same as origin slice
 	//mp := make(map[interface{}]bool)
@@ -411,6 +417,66 @@ func Unique(slice interface{}) interface{} {
 
 }
 
+// Union creates an slice of unique values, in order, from all given slices. using == for equality comparisons.
+func Union(slices ...interface{}) interface{} {
+	if len(slices) == 0 {
+		return nil
+	}
+	// append all slices, then unique it
+	var allSlice []interface{}
+	len := 0
+	for i := range slices {
+		sv := sliceValue(slices[i])
+		len += sv.Len()
+		for j := 0; j < sv.Len(); j++ {
+			v := sv.Index(j).Interface()
+			allSlice = append(allSlice, v)
+		}
+	}
+
+	sv := sliceValue(slices[0])
+	res := reflect.MakeSlice(sv.Type(), len, len)
+	for i := 0; i < len; i++ {
+		res.Index(i).Set(reflect.ValueOf(allSlice[i]))
+	}
+
+	return Unique(res.Interface())
+}
+
+// Intersection creates an slice of unique values that included by all slices.
+func Intersection(slices ...interface{}) interface{} {
+	if len(slices) == 0 {
+		return nil
+	}
+
+	reduceFunc := func(index int, slice1, slice2 interface{}) interface{} {
+		set := make([]interface{}, 0)
+		hash := make(map[interface{}]bool)
+
+		sv1 := reflect.ValueOf(slice1)
+		for i := 0; i < sv1.Len(); i++ {
+			v := sv1.Index(i).Interface()
+			hash[v] = true
+		}
+
+		sv2 := reflect.ValueOf(slice2)
+		for i := 0; i < sv2.Len(); i++ {
+			el := sv2.Index(i).Interface()
+			if _, found := hash[el]; found {
+				set = append(set, el)
+			}
+		}
+		res := reflect.MakeSlice(sv1.Type(), len(set), len(set))
+		for i := 0; i < len(set); i++ {
+			res.Index(i).Set(reflect.ValueOf(set[i]))
+		}
+		return res.Interface()
+	}
+
+	res := Reduce(slices, reduceFunc, nil)
+	return Union(res)
+}
+
 // ReverseSlice return slice of element order is reversed to the given slice
 func ReverseSlice(slice interface{}) {
 	v := sliceValue(slice)
@@ -474,3 +540,25 @@ func SortByField(slice interface{}, field string, sortType ...string) error {
 	}
 	return nil
 }
+
+// Without creates an array excluding all given values
+func Without(slice interface{}, values ...interface{}) interface{} {
+	sv := sliceValue(slice)
+	if sv.Len() == 0 {
+		return slice
+	}
+	var indexes []int
+	for i := 0; i < sv.Len(); i++ {
+		v := sv.Index(i).Interface()
+		if !Contain(values, v) {
+			indexes = append(indexes, i)
+		}
+	}
+
+	res := reflect.MakeSlice(sv.Type(), len(indexes), len(indexes))
+	for i := range indexes {
+		res.Index(i).Set(sv.Index(indexes[i]))
+	}
+
+	return res.Interface()
+}

slice/slice_test.go

@@ -395,7 +395,7 @@ func updateByIndex(t *testing.T, test interface{}, index int, value, expected in
 func TestUnique(t *testing.T) {
 	t1 := []int{1, 2, 2, 3}
 	e1 := []int{1, 2, 3}
-	r1, _ := IntSlice(Unique(t1))
+	r1 := Unique(t1)
 	if !reflect.DeepEqual(r1, e1) {
 		utils.LogFailedTestInfo(t, "Unique", t1, e1, r1)
 		t.FailNow()
@@ -403,13 +403,60 @@ func TestUnique(t *testing.T) {
 
 	t2 := []string{"a", "a", "b", "c"}
 	e2 := []string{"a", "b", "c"}
-	r2 := StringSlice(Unique(t2))
+	r2 := Unique(t2)
 	if !reflect.DeepEqual(r2, e2) {
 		utils.LogFailedTestInfo(t, "Unique", t2, e2, r2)
 		t.FailNow()
 	}
 }
 
+func TestUnion(t *testing.T) {
+	s1 := []int{1, 3, 4, 6}
+	s2 := []int{1, 2, 5, 6}
+	s3 := []int{0, 4, 5, 7}
+
+	expected1 := []int{1, 3, 4, 6, 2, 5, 0, 7}
+	res1 := Union(s1, s2, s3)
+	if !reflect.DeepEqual(res1, expected1) {
+		utils.LogFailedTestInfo(t, "Union", s1, expected1, res1)
+		t.FailNow()
+	}
+
+	expected2 := []int{1, 3, 4, 6}
+	res2 := Union(s1)
+	if !reflect.DeepEqual(res2, expected2) {
+		utils.LogFailedTestInfo(t, "Union", s1, expected2, res2)
+		t.FailNow()
+	}
+}
+
+func TestIntersection(t *testing.T) {
+	s1 := []int{1, 2, 2, 3}
+	s2 := []int{1, 2, 3, 4}
+	s3 := []int{0, 2, 3, 5, 6}
+	s4 := []int{0, 5, 6}
+
+	expected := [][]int{
+		{2, 3},
+		{1, 2, 3},
+		{1, 2, 3},
+		{},
+	}
+	res := []interface{}{
+		Intersection(s1, s2, s3),
+		Intersection(s1, s2),
+		Intersection(s1),
+		Intersection(s1, s4),
+	}
+	for i := 0; i < len(res); i++ {
+		if !reflect.DeepEqual(res[i], expected[i]) {
+			utils.LogFailedTestInfo(t, "Intersection", "Intersection", expected[i], res[i])
+			t.FailNow()
+		}
+	}
+
+}
+
 func TestReverseSlice(t *testing.T) {
 	s1 := []int{1, 2, 3, 4, 5}
 	e1 := []int{5, 4, 3, 2, 1}
@@ -469,3 +516,14 @@ func TestSortByField(t *testing.T) {
 	}
 
 }
+
+func TestWithout(t *testing.T) {
+	s := []int{1, 2, 3, 4, 5}
+	expected := []int{3, 4, 5}
+	res := Without(s, 1, 2)
+
+	if !reflect.DeepEqual(res, expected) {
+		utils.LogFailedTestInfo(t, "Without", s, expected, res)
+		t.FailNow()
+	}
+}