feat: add FindValuesBy

maputil/map.go

@@ -666,3 +666,17 @@ func GetOrDefault[K comparable, V any](m map[K]V, key K, defaultValue V) V {
 	}
 	return defaultValue
 }
+
+// FindValuesBy returns a slice of values from the map that satisfy the given predicate function.
+// Play: todo
+func FindValuesBy[K comparable, V any](m map[K]V, predicate func(key K, value V) bool) []V {
+	result := make([]V, 0)
+
+	for k, v := range m {
+		if predicate(k, v) {
+			result = append(result, v)
+		}
+	}
+
+	return result
+}

maputil/map_example_test.go

@@ -829,3 +829,21 @@ func ExampleOrderedMap_UnmarshalJSON() {
 
 	// fmt.Println(om.Elements())
 }
+
+func ExampleFindValuesBy() {
+	m := map[int]string{
+		1: "a",
+		2: "b",
+		3: "c",
+		4: "d",
+	}
+
+	result := FindValuesBy(m, func(k int, v string) bool {
+		return k%2 == 0
+	})
+
+	fmt.Println(result)
+
+	// Output:
+	// [b d]
+}

maputil/map_test.go

@@ -888,3 +888,41 @@ func TestGetOrDefault(t *testing.T) {
 	result2 := GetOrDefault(m1, 5, "123")
 	assert.Equal("123", result2)
 }
+
+func TestFindValuesBy(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestFindValuesBy")
+
+	tests := []struct {
+		name     string
+		inputMap map[string]string
+		key      string
+		expected []string
+	}{
+		{
+			name:     "Key exists",
+			inputMap: map[string]string{"a": "1", "b": "2", "c": "3"},
+			key:      "b",
+			expected: []string{"2"},
+		},
+		{
+			name:     "Key does not exist",
+			inputMap: map[string]string{"a": "1", "b": "2", "c": "3"},
+			key:      "d",
+			expected: []string{},
+		},
+		{
+			name:     "Empty map",
+			inputMap: map[string]string{},
+			key:      "a",
+			expected: []string{},
+		},
+	}
+	for _, tt := range tests {
+		result := FindValuesBy(tt.inputMap, func(key string, value string) bool {
+			return key == tt.key
+		})
+		assert.Equal(tt.expected, result)
+	}
+}