Merge pull request #9 from devalexandre/feat-otmization

Feat otmization

.gitignore

@@ -13,3 +13,4 @@
 
 # Dependency directories (remove the comment below to include it)
 # vendor/
+.*benchmark*.

array/array.go

@@ -28,8 +28,8 @@ func (a *Array[T]) Filter(f func(T) bool) *Array[T] {
 	return &Array[T]{value: Filter(a.value, f)}
 }
 
-func (a *Array[T]) Find(f func(T) bool) *T {
-	return Find(&a.value, f)
+func (a *Array[T]) Find(f func(T) bool) (T, bool) {
+	return Find(a.value, f)
 }
 
 func (a *Array[T]) Map(f func(T) T) *Array[T] {

array/array_test.go

@@ -17,8 +17,8 @@ func TestArray(t *testing.T) {
 
 	t.Run("test Find", func(t *testing.T) {
 		a := []int{1, 2, 3, 4, 5}
-		b := array.NewArray(a).Find(func(x int) bool { return x%2 == 0 })
-		if *b != 2 {
+		b, _ := array.NewArray(a).Find(func(x int) bool { return x%2 == 0 })
+		if b != 2 {
 			t.Error("Find failed. Got", b, "Expected", 2)
 		}
 	})

array/functions.go

@@ -18,23 +18,39 @@ type Number interface {
  *   b := Filter(a, func(x int) bool { return x%2 == 0 })
  *   fmt.Println(b) // [2 4]
  */
+
 func Filter[T any](a []T, f func(T) bool) []T {
-	var b []T
+	y := make([]T, len(a))
+	i := 0
 	for _, x := range a {
 		if f(x) {
-			b = append(b, x)
+			y[i] = x
+			i++
 		}
 	}
-	return b
+	return y[:i]
+}
+
+//with side effects
+func Filter0Loc[T any](a []T, f func(T) bool) []T {
+	i := 0
+	for _, x := range a {
+		if f(x) {
+			a[i] = x
+			i++
+		}
+	}
+	return a[:i]
 }
 
-func Find[T any](a *[]T, f func(T) bool) *T {
-	for _, x := range *a {
+func Find[T any](a []T, f func(T) bool) (T, bool) {
+	for _, x := range a {
 		if f(x) {
-			return &x
+			return x, true
 		}
 	}
-	return nil
+	var zero T
+	return zero, false
 }
 
 /* Map
@@ -45,13 +61,21 @@ func Find[T any](a *[]T, f func(T) bool) *T {
  */
 
 func Map[T, U any](a []T, f func(T) U) []U {
-	var b []U
-	for _, x := range a {
-		b = append(b, f(x))
+	var b = make([]U, len(a))
+	for i := 0; i < len(a); i++ {
+		b[i] = f(a[i])
 	}
+
 	return b
 }
 
+//with side effects
+func Map0Loc[T any](a []T, f func(T) T) {
+	for i, x := range a {
+		a[i] = f(x)
+	}
+}
+
 /* FlatMap
 * Example:
 *   a := []int{1, 2, 3, 4, 5}
@@ -416,5 +440,6 @@ func GroupBy[T any, K comparable](w []T, key func(T) K) map[K][]T {
 			m[key(x)] = make([]T, 0)
 		}
 	}
+
 	return m
 }

array/functions_test.go

@@ -14,14 +14,34 @@ func TestFilter(t *testing.T) {
 	if !reflect.DeepEqual(b, []int{2, 4}) {
 		t.Error("Filter failed. Got", b, "Expected", []int{2, 4})
 	}
+
+	if len(a) == len(b) {
+		t.Error("Filter failed. Got", len(a), "Expected", len(b))
+	}
+
+	fmt.Println(a)
+}
+
+func TestFilter0Loc(t *testing.T) {
+	a := []int{1, 2, 3, 4, 5}
+	b := array.Filter0Loc(a, func(x int) bool { return x%2 == 0 })
+	if !reflect.DeepEqual(b, []int{2, 4}) {
+		t.Error("Filter failed. Got", b, "Expected", []int{2, 4})
+	}
+
+	if len(a) == len(b) {
+		t.Error("Filter failed. Got", len(a), "Expected", len(b))
+	}
+
+	fmt.Println(a)
 }
 
 //test array.Find
 func TestFind(t *testing.T) {
 	a := []int{1, 2, 3, 4, 5}
-	b := array.Find(&a, func(x int) bool { return x%2 == 0 })
-	if *b != 2 {
-		t.Error("Find failed. Got", *b, "Expected", 2)
+	b, _ := array.Find(a, func(x int) bool { return x%2 == 0 })
+	if b != 2 {
+		t.Error("Find failed. Got", b, "Expected", 2)
 	}
 }