From 32b4ea027b17fabe4b2409742895377d7a4a5855 Mon Sep 17 00:00:00 2001
From: Sterling Hanenkamp <sterling@hanenkamp.com>
Date: Sun, 28 May 2023 15:25:21 -0500
Subject: [PATCH] Adding the Keys method to set.Set

---
 Changes.md      |  4 ++++
 README.md       |  1 +
 set/set.go      |  8 ++++++++
 set/set_test.go | 26 ++++++++++++++++++++++++++
 4 files changed, 39 insertions(+)

diff --git a/Changes.md b/Changes.md
index a762b37..6a3dc61 100644
--- a/Changes.md
+++ b/Changes.md
@@ -1,3 +1,7 @@
+WIP  TBD
+
+ * Added set.Set.Keys method.
+
 v0.1.0  2023-05-27
 
  * Added generic.CountDeltas function.
diff --git a/README.md b/README.md
index 63708fc..625b02e 100644
--- a/README.md
+++ b/README.md
@@ -87,6 +87,7 @@ following methods on sets:
  * `Delete(val)`
  * `Len()`
  * `SubsetOf(set)`
+ * `Keys()`
 
 And then it also provides these functions to work on sets:
 
diff --git a/set/set.go b/set/set.go
index aa55c46..b9d0a83 100644
--- a/set/set.go
+++ b/set/set.go
@@ -1,5 +1,7 @@
 package set
 
+import "github.com/zostay/go-std/maps"
+
 // Set provides a generic set data type. A set is an unsorted list of objects
 // where each object is unique, as defined by the equivalence operation. These
 // are implemented using a map. Any value that can be used as a map key can be
@@ -54,6 +56,12 @@ func (s Set[T]) SubsetOf(o Set[T]) bool {
 	return true
 }
 
+// Keys returns all the keys in the set as a slice. The return slice is
+// unsorted and the keys returned could be in any order.
+func (s Set[T]) Keys() []T {
+	return maps.Keys(s)
+}
+
 // Intersects returns true if any value in set a is found within set b.
 func Intersects[T comparable](a, b Set[T]) bool {
 	for val := range a {
diff --git a/set/set_test.go b/set/set_test.go
index 05e0844..0570a9e 100644
--- a/set/set_test.go
+++ b/set/set_test.go
@@ -108,6 +108,32 @@ func TestSet_SubsetOf(t *testing.T) {
 	assert.True(t, s3.SubsetOf(s3))
 }
 
+func TestSet_Keys(t *testing.T) {
+	s1 := set.New(1, 2, 3)
+	s2 := set.New(2, 3)
+	s3 := set.New(3, 4)
+	s4 := set.New[int]()
+
+	keys := s1.Keys()
+	assert.Len(t, keys, 3)
+	assert.Contains(t, keys, 1)
+	assert.Contains(t, keys, 2)
+	assert.Contains(t, keys, 3)
+
+	keys = s2.Keys()
+	assert.Len(t, keys, 2)
+	assert.Contains(t, keys, 2)
+	assert.Contains(t, keys, 3)
+
+	keys = s3.Keys()
+	assert.Len(t, keys, 2)
+	assert.Contains(t, keys, 3)
+	assert.Contains(t, keys, 4)
+
+	keys = s4.Keys()
+	assert.Len(t, keys, 0)
+}
+
 func TestDifference(t *testing.T) {
 	s1 := set.New(1, 2, 3)
 	s2 := set.New(3, 4, 5)