Add Set implementation

Author: zegabr

set.go

@@ -0,0 +1,89 @@
+package collections
+
+import (
+	"fmt"
+	"strings"
+)
+
+// Collection that stores a set of homogenous elements.
+type Set[T CollectionElement] struct {
+	items map[T]struct{}
+}
+
+// Factory method to create an empty set with predefined capacity.
+func NewSet[T CollectionElement]() *Set[T] {
+	s := &Set[T]{}
+	s.items = make(map[T]struct{})
+	return s
+}
+
+// Factory method to create a set from an array.
+func ToSet[T CollectionElement](array []T) *Set[T] {
+	s := &Set[T]{}
+	s.items = make(map[T]struct{}, len(array))
+	for _, item := range array {
+		s.items[item] = struct{}{}
+	}
+	return s
+}
+
+// Add element to set.
+func (s *Set[T]) Add(item T) {
+	s.items[item] = struct{}{}
+}
+
+// Checks whether an element is present in the set.
+func (s *Set[T]) Contains(item T) bool {
+	_, ok := s.items[item]
+	return ok
+}
+
+// Updates the current set to be it's union with another set.
+func (s *Set[T]) Extend(s2 *Set[T]) {
+	for key := range s2.items {
+		s.items[key] = struct{}{}
+	}
+}
+
+// Removes all elements from the set.
+func (s *Set[T]) Clear() {
+	s.items = make(map[T]struct{})
+}
+
+// Removes occurence of the given element from the set.
+// Returns an error if the element is not present in the set.
+func (s *Set[T]) Remove(item T) error {
+	if _, ok := s.items[item]; !ok {
+		return ErrItemNotFound
+	}
+	delete(s.items, item)
+	return nil
+}
+
+// Returns an slice containing elements of the set.
+func (s *Set[T]) ToArray() []T {
+	result := make([]T, 0, s.Size())
+	for key := range s.items {
+		result = append(result, key)
+	}
+	return result
+}
+
+// Returns the number of elements in the set.
+func (s Set[T]) Size() int {
+	return len(s.items)
+}
+
+// Returns a string description of the set.
+func (s Set[T]) String() string {
+	resultStrings := make([]string, 0, s.Size())
+	for e := range s.items {
+		resultStrings = append(resultStrings, fmt.Sprint(e))
+	}
+
+	return "{" + strings.Join(resultStrings, ",") + "}"
+}
+
+func (_ Set[T]) Type() CollectionType {
+	return TypeSet
+}