feat: add FilterConcurrent

slice/slice_concurrent.go

@@ -8,7 +8,7 @@ import (
 	"sync"
 )
 
-// MapConcurrent applies the iteratee function to each item in the slice by concrrent.
+// MapConcurrent applies the iteratee function to each item in the slice concurrently.
 // Play: todo
 func MapConcurrent[T any, U any](slice []T, numOfThreads int, iteratee func(index int, item T) U) []U {
 	result := make([]U, len(slice))
@@ -35,6 +35,35 @@ func MapConcurrent[T any, U any](slice []T, numOfThreads int, iteratee func(inde
 	return result
 }
 
+// FilterConcurrent applies the provided filter function `predicate` to each element of the input slice concurrently.
+// Play: todo
+func FilterConcurrent[T any](slice []T, numOfThreads int, predicate func(index int, item T) bool) []T {
+	result := make([]T, 0)
+	var wg sync.WaitGroup
+
+	workerChan := make(chan struct{}, numOfThreads)
+
+	for index, item := range slice {
+		wg.Add(1)
+
+		workerChan <- struct{}{}
+
+		go func(i int, v T) {
+			defer wg.Done()
+
+			if predicate(i, v) {
+				result = append(result, v)
+			}
+
+			<-workerChan
+		}(index, item)
+	}
+
+	wg.Wait()
+
+	return result
+}
+
 // UniqueByParallel removes duplicate elements from the slice by parallel
 // The comparator function is used to compare the elements
 // The numOfThreads parameter specifies the number of threads to use

slice/slice_example_test.go

@@ -247,6 +247,21 @@ func ExampleFilter() {
 	// [2 4]
 }
 
+func ExampleFilterConcurrent() {
+	nums := []int{1, 2, 3, 4, 5}
+
+	isEven := func(i, num int) bool {
+		return num%2 == 0
+	}
+
+	result := FilterConcurrent(nums, 2, isEven)
+
+	fmt.Println(result)
+
+	// Output:
+	// [2 4]
+}
+
 func ExampleCount() {
 	nums := []int{1, 2, 3, 3, 4}
 

slice/slice_test.go

@@ -1542,3 +1542,29 @@ func TestMapConcurrent(t *testing.T) {
 	})
 
 }
+
+func TestFilterConcurrent(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestFilterConcurrent")
+
+	t.Run("empty slice", func(t *testing.T) {
+		actual := FilterConcurrent([]int{}, 4, func(_, n int) bool { return n != 0 })
+		assert.Equal([]int{}, actual)
+	})
+
+	t.Run("single thread", func(t *testing.T) {
+		nums := []int{1, 2, 3, 4, 5, 6}
+		expected := []int{4, 5, 6}
+		actual := FilterConcurrent(nums, 1, func(_, n int) bool { return n > 3 })
+		assert.Equal(expected, actual)
+	})
+
+	t.Run("multiple threads", func(t *testing.T) {
+		nums := []int{1, 2, 3, 4, 5, 6}
+		expected := []int{4, 5, 6}
+		actual := FilterConcurrent(nums, 4, func(_, n int) bool { return n > 3 })
+		assert.Equal(expected, actual)
+	})
+
+}