initial commit

pkg/array/diff.go

@@ -0,0 +1,75 @@
+package array
+
+func Diff[T comparable](slice1, slice2 []T) []T {
+	var result []T
+
+	elementsMap := make(map[T]bool)
+	for _, v := range slice2 {
+		elementsMap[v] = true
+	}
+
+	for _, v := range slice1 {
+		if !elementsMap[v] {
+			result = append(result, v)
+		}
+	}
+
+	return result
+}
+
+func MapDiff[T comparable](slice1, slice2 []T) []T {
+	var result []T
+
+	arr1elementsMap := make(map[T]int)
+	for _, v := range slice1 {
+		arr1elementsMap[v] += 1
+	}
+
+	arr2elementsMap := make(map[T]int)
+	for _, v := range slice2 {
+		arr2elementsMap[v] += 1
+	}
+
+	for key, count1 := range arr1elementsMap {
+		if count2, ok := arr2elementsMap[key]; !ok || count2 != count1 {
+			result = append(result, key)
+		}
+	}
+
+	return result
+}
+
+// DiffByKeyAndValue returns the elements from slice1 that do not have
+// corresponding elements in slice2 based on a key and a comparison function.
+// T1 and T2 are the types of the elements in slice1 and slice2 respectively.
+// K is the type of the key used for comparison.
+func DiffByKeyAndValue[T1 any, T2 any, K comparable](
+	slice1 []T1,
+	slice2 []T2,
+	getKeyFromSlice1 func(T1) K,
+	getKeyFromSlice2 func(T2) K,
+	compare func(T1, T2) bool,
+) []T1 {
+	// Create a map to index elements of slice2 by their keys
+	indexedSlice2 := make(map[K]T2)
+	for _, elementFromSlice2 := range slice2 {
+		key := getKeyFromSlice2(elementFromSlice2)
+		indexedSlice2[key] = elementFromSlice2
+	}
+
+	// Initialize a slice to hold the elements that are different
+	var differingElements []T1
+
+	// Iterate over slice1 and find elements that are not in slice2
+	for _, elementFromSlice1 := range slice1 {
+		key := getKeyFromSlice1(elementFromSlice1)
+
+		// Check if the key exists in the indexed slice2
+		if correspondingElementFromSlice2, exists := indexedSlice2[key]; !exists || !compare(elementFromSlice1, correspondingElementFromSlice2) {
+			// If it doesn't exist or the comparison fails, add to the result
+			differingElements = append(differingElements, elementFromSlice1)
+		}
+	}
+
+	return differingElements
+}