#13 - RemoveMatching methods return the number of removed items

common_test.go

@@ -34,6 +34,7 @@ type testCase[C any, V any] struct {
 	want2       any
 	want3       any
 	want4       any
+	want5       any
 	got1        any
 	got2        any
 	got3        any

definitions.go

@@ -89,7 +89,7 @@ type Mutable[V any] interface {
 	Clear()
 
 	// RemoveMatching removes all elements that match the given predicate.
-	RemoveMatching(predicate Predicate[V]) // TODO: return count of removed items
+	RemoveMatching(predicate Predicate[V]) (count int)
 }
 
 // IndexedMutable is a mutable collection that can be modified based on the indexes.

functions_internal.go

@@ -58,17 +58,20 @@ func sliceRemoveAt[V any](s []V, i int) (removed V, newSLice []V, err error) {
 }
 
 // sliceRemoveMatching removes all elements for which the predicate returns true.
-func sliceRemoveMatching[V any](s []V, predicate Predicate[V]) []V {
+func sliceRemoveMatching[V any](s []V, predicate Predicate[V]) ([]V, int) {
+	removed := 0
 	newS := make([]V, 0, len(s))
 	for _, v := range s {
 		if !predicate(v) {
 			newS = append(newS, v)
+		} else {
+			removed++
 		}
 	}
 
 	if len(newS) == 0 {
-		return []V(nil)
+		return []V(nil), removed
 	}
 
-	return newS
+	return newS, removed
 }

map.go

@@ -148,7 +148,7 @@ func (c *comfyMap[K, V]) RemoveMany(keys []K) {
 	c.removeMany(keys)
 }
 
-func (c *comfyMap[K, V]) RemoveMatching(predicate Predicate[Pair[K, V]]) {
+func (c *comfyMap[K, V]) RemoveMatching(predicate Predicate[Pair[K, V]]) (count int) {
 	newS := []Pair[K, V](nil)
 	newM := make(map[K]Pair[K, V])
 	newKP := make(map[K]int)
@@ -160,12 +160,15 @@ func (c *comfyMap[K, V]) RemoveMatching(predicate Predicate[Pair[K, V]]) {
 			newM[pair.Key()] = pair
 			newKP[pair.Key()] = idx
 			idx++
+		} else {
+			count++
 		}
 	}
 
 	c.s = newS
 	c.m = newM
 	c.kp = newKP
+	return count
 }
 
 func (c *comfyMap[K, V]) Reverse() {

map_cases_test.go

@@ -1449,6 +1449,7 @@ func getMapRemoveMatchingCases(builder baseMapCollIntBuilder) []baseMapTestCase
 			want2: map[int]int{},
 			want3: map[int]int{},
 			want4: map[int]int{},
+			want5: 0,
 		},
 		{
 			name:  "RemoveMatching() on one-item collection, found",
@@ -1458,6 +1459,7 @@ func getMapRemoveMatchingCases(builder baseMapCollIntBuilder) []baseMapTestCase
 			want2: map[int]int{},
 			want3: map[int]int{},
 			want4: map[int]int{},
+			want5: 1,
 		},
 		{
 			name:  "RemoveMatching() on one-item collection, not found",
@@ -1467,6 +1469,7 @@ func getMapRemoveMatchingCases(builder baseMapCollIntBuilder) []baseMapTestCase
 			want2: map[int]int{1: 111},
 			want3: map[int]int{1: 0},
 			want4: map[int]int{111: 1},
+			want5: 0,
 		},
 		{
 			name:  "RemoveMatching() on three-item collection, found all",
@@ -1476,6 +1479,7 @@ func getMapRemoveMatchingCases(builder baseMapCollIntBuilder) []baseMapTestCase
 			want2: map[int]int{},
 			want3: map[int]int{},
 			want4: map[int]int{},
+			want5: 3,
 		},
 		{
 			name:  "RemoveMatching() on three-item collection, found none",
@@ -1485,6 +1489,7 @@ func getMapRemoveMatchingCases(builder baseMapCollIntBuilder) []baseMapTestCase
 			want2: map[int]int{1: 111, 2: 222, 3: 333},
 			want3: map[int]int{1: 0, 2: 1, 3: 2},
 			want4: map[int]int{111: 1, 222: 1, 333: 1},
+			want5: 0,
 		},
 		{
 			name:  "RemoveMatching() on three-item collection, found first",
@@ -1494,6 +1499,7 @@ func getMapRemoveMatchingCases(builder baseMapCollIntBuilder) []baseMapTestCase
 			want2: map[int]int{2: 222, 3: 333},
 			want3: map[int]int{2: 0, 3: 1},
 			want4: map[int]int{222: 1, 333: 1},
+			want5: 1,
 		},
 		{
 			name:  "RemoveMatching() on three-item collection, found middle",
@@ -1503,6 +1509,7 @@ func getMapRemoveMatchingCases(builder baseMapCollIntBuilder) []baseMapTestCase
 			want2: map[int]int{1: 111, 3: 333},
 			want3: map[int]int{1: 0, 3: 1},
 			want4: map[int]int{111: 1, 333: 1},
+			want5: 1,
 		},
 		{
 			name:  "RemoveMatching() on three-item collection, found last",
@@ -1512,6 +1519,17 @@ func getMapRemoveMatchingCases(builder baseMapCollIntBuilder) []baseMapTestCase
 			want2: map[int]int{1: 111, 2: 222},
 			want3: map[int]int{1: 0, 2: 1},
 			want4: map[int]int{111: 1, 222: 1},
+			want5: 1,
+		},
+		{
+			name:  "RemoveMatching() on three-item collection, found even",
+			coll:  builder.Three(),
+			args:  baseMapIntArgs{predicate: func(p Pair[int, int]) bool { return p.Val()%2 != 0 }},
+			want1: []Pair[int, int]{NewPair(2, 222)},
+			want2: map[int]int{2: 222},
+			want3: map[int]int{2: 0},
+			want4: map[int]int{222: 1},
+			want5: 2,
 		},
 	}
 }
@@ -1520,7 +1538,7 @@ func testMapRemoveMatching(t *testing.T, builder baseMapCollIntBuilder) {
 	cases := getMapRemoveMatchingCases(builder)
 	for _, tt := range cases {
 		t.Run(tt.name, func(t *testing.T) {
-			tt.coll.RemoveMatching(tt.args.predicate)
+			count := tt.coll.RemoveMatching(tt.args.predicate)
 			actualSlice := builder.extractUnderlyingSlice(tt.coll)
 			actualMap := builder.extractUnderlyingMap(tt.coll)
 			actualKP := builder.extractUnderlyingKp(tt.coll)
@@ -1539,6 +1557,9 @@ func testMapRemoveMatching(t *testing.T, builder baseMapCollIntBuilder) {
 					t.Errorf("RemoveMatching() did not remove correctly from values counter")
 				}
 			}
+			if count != tt.want5 {
+				t.Errorf("RemoveMatching() returned wrong count: %v, but wanted = %v", count, tt.want5)
+			}
 		})
 	}
 }

mapcmp.go

@@ -190,7 +190,7 @@ func (c *comfyCmpMap[K, V]) RemoveMany(keys []K) {
 	c.removeMany(keys)
 }
 
-func (c *comfyCmpMap[K, V]) RemoveMatching(predicate Predicate[Pair[K, V]]) {
+func (c *comfyCmpMap[K, V]) RemoveMatching(predicate Predicate[Pair[K, V]]) (count int) {
 	newS := []Pair[K, V](nil)
 	newM := make(map[K]Pair[K, V])
 	newKP := make(map[K]int)
@@ -204,13 +204,16 @@ func (c *comfyCmpMap[K, V]) RemoveMatching(predicate Predicate[Pair[K, V]]) {
 			newKP[pair.Key()] = idx
 			newVC.Increment(pair.Val())
 			idx++
+		} else {
+			count++
 		}
 	}
 
 	c.s = newS
 	c.m = newM
 	c.kp = newKP
 	c.vc = newVC
+	return count
 }
 
 func (c *comfyCmpMap[K, V]) RemoveValues(v V) {

mutable_cases_test.go

@@ -111,48 +111,55 @@ func getRemoveMatchingCases(builder mutableIntTestBuilder) []mutableIntTestCase
 			args:  mutableIntTestArgs{predicate: func(v int) bool { return true }},
 			want1: []int(nil),
 			want2: map[int]int{},
+			want3: 0,
 		},
 		{
 			name:  "RemoveMatching() on one-item collection",
 			coll:  builder.One(),
 			args:  mutableIntTestArgs{predicate: func(v int) bool { return v == 111 }},
 			want1: []int(nil),
 			want2: map[int]int{},
+			want3: 1,
 		},
 		{
 			name:  "RemoveMatching() on three-item collection",
 			coll:  builder.Three(),
 			args:  mutableIntTestArgs{predicate: func(v int) bool { return v == 222 }},
 			want1: []int{111, 333},
 			want2: map[int]int{111: 1, 333: 1},
+			want3: 1,
 		},
 		{
 			name:  "RemoveMatching() on three-item collection, all false",
 			coll:  builder.Three(),
 			args:  mutableIntTestArgs{predicate: func(v int) bool { return false }},
 			want1: []int{111, 222, 333},
 			want2: map[int]int{111: 1, 222: 1, 333: 1},
+			want3: 0,
 		},
 		{
 			name:  "RemoveMatching() on three-item collection, all true",
 			coll:  builder.Three(),
 			args:  mutableIntTestArgs{predicate: func(v int) bool { return true }},
 			want1: []int(nil),
 			want2: map[int]int{},
+			want3: 3,
 		},
 		{
 			name:  "RemoveMatching() on three-item collection, some mod 2",
 			coll:  builder.Three(),
 			args:  mutableIntTestArgs{predicate: func(v int) bool { return v%2 == 0 }},
 			want1: []int{111, 333},
 			want2: map[int]int{111: 1, 333: 1},
+			want3: 1,
 		},
 		{
 			name:  "RemoveMatching() on three-item collection, some not mod 2",
 			coll:  builder.Three(),
 			args:  mutableIntTestArgs{predicate: func(v int) bool { return v%2 != 0 }},
 			want1: []int{222},
 			want2: map[int]int{222: 1},
+			want3: 2,
 		},
 	}
 }
@@ -161,7 +168,7 @@ func testRemoveMatching(t *testing.T, builder mutableIntTestBuilder) {
 	cases := getRemoveMatchingCases(builder)
 	for _, tt := range cases {
 		t.Run(tt.name, func(t *testing.T) {
-			tt.coll.RemoveMatching(tt.args.predicate)
+			count := tt.coll.RemoveMatching(tt.args.predicate)
 
 			actualSlice := builder.extractUnderlyingSlice(tt.coll)
 			actualVC := builder.extractUnderlyingValsCount(tt.coll)
@@ -172,6 +179,9 @@ func testRemoveMatching(t *testing.T, builder mutableIntTestBuilder) {
 			if actualVC != nil && !reflect.DeepEqual(actualVC, tt.want2) {
 				t.Errorf("RemoveMatching() did not remove correctly from values counter")
 			}
+			if count != tt.want3 {
+				t.Errorf("RemoveMatching() returned wrong count: %v, but wanted = %v", count, tt.want3)
+			}
 		})
 	}
 }

sequence.go

@@ -93,8 +93,9 @@ func (c *comfySeq[V]) RemoveAt(i int) (removed V, err error) {
 	return removed, nil
 }
 
-func (c *comfySeq[V]) RemoveMatching(predicate Predicate[V]) {
-	c.s = sliceRemoveMatching(c.s, predicate)
+func (c *comfySeq[V]) RemoveMatching(predicate Predicate[V]) (count int) {
+	c.s, count = sliceRemoveMatching(c.s, predicate)
+	return count
 }
 
 func (c *comfySeq[V]) Reverse() {

sequencecmp.go

@@ -140,17 +140,20 @@ func (c *comfyCmpSeq[V]) RemoveAt(i int) (removed V, err error) {
 	return removed, nil
 }
 
-func (c *comfyCmpSeq[V]) RemoveMatching(predicate Predicate[V]) {
+func (c *comfyCmpSeq[V]) RemoveMatching(predicate Predicate[V]) (count int) {
 	newS := []V(nil)
 	newVC := newValuesCounter[V]()
 	for _, v := range c.s {
 		if !predicate(v) {
 			newS = append(newS, v)
 			newVC.Increment(v)
+		} else {
+			count++
 		}
 	}
 	c.s = newS
 	c.vc = newVC
+	return count
 }
 
 func (c *comfyCmpSeq[V]) RemoveValues(v V) {