CrossJoinX + CrossJoinByX

Author: samber

README.md

@@ -122,7 +122,6 @@ Supported helpers for slices:
 - [IsSorted](#issorted)
 - [IsSortedByKey](#issortedbykey)
 - [Splice](#Splice)
-- [CrossJoin](#CrossJoin)
 
 Supported helpers for maps:
 
@@ -178,6 +177,8 @@ Supported helpers for tuples:
 - [ZipBy2 -> ZipBy9](#zipby2---zipby9)
 - [Unzip2 -> Unzip9](#unzip2---unzip9)
 - [UnzipBy2 -> UnzipBy9](#unzipby2---unzipby9)
+- [CrossJoin2 -> CrossJoin2](#crossjoin2---crossjoin9)
+- [CrossJoinBy2 -> CrossJoinBy2](#crossjoinby2---crossjoinby9)
 
 Supported helpers for time and duration:
 
@@ -1064,19 +1065,6 @@ result = lo.Splice([]string{"a", "b"}, 42, "1", "2")
 
 [[play](https://go.dev/play/p/wiG6XyBBu49)]
 
-### CrossJoin
-
-CrossJoin calculates the cartesian product of two lists. It returns a list of tuples where the first element includes the elements of the first parameter, and the second element contains the elements of the second parameter.
-
-It returns an empty list if either, or both parameters are empty
-
-```go
-result := lo.CrossJoin([]string{"a", "b", "c"}, []int{1, 2, 3})
-// [][2]interface{}{{"a", 1}, {"a", 2}, {"a", 3}, {"b", 1}, {"b", 2}, {"b", 3}, {"c", 1}, {"c", 2}, {"c", 3}
-```
-
-[[play](https://go.dev/play/p/2-DOGciKvAB)]
-
 ### Keys
 
 Creates a slice of the map keys.
@@ -1710,6 +1698,36 @@ a, b := lo.UnzipBy2([]string{"hello", "john", "doe"}, func(str string) (string,
 // []int{5, 4, 3}
 ```
 
+### CrossJoin2 -> CrossJoin9
+
+Combines every items from one list with every items from others. It is the cartesian product of lists received as arguments. It returns an empty list if a list is empty.
+
+```go
+result := lo.CrossJoin2([]string{"hello", "john", "doe"}, []int{1, 2})
+// lo.Tuple2{"hello", 1}
+// lo.Tuple2{"hello", 2}
+// lo.Tuple2{"john", 1}
+// lo.Tuple2{"john", 2}
+// lo.Tuple2{"doe", 1}
+// lo.Tuple2{"doe", 2}
+```
+
+### CrossJoinBy2 -> CrossJoinBy9
+
+Combines every items from one list with every items from others. It is the cartesian product of lists received as arguments. The project function is used to create the output values. It returns an empty list if a list is empty.
+
+```go
+result := lo.CrossJoinBy2([]string{"hello", "john", "doe"}, []int{1, 2}, func(a A, b B) string {
+    return fmt.Sprintf("%s - %d", a, b)
+})
+// "hello - 1"
+// "hello - 2"
+// "john - 1"
+// "john - 2"
+// "doe - 1"
+// "doe - 2"
+```
+
 ### Duration
 
 Returns the time taken to execute a function.

slice.go

@@ -708,27 +708,3 @@ func Splice[T any, Slice ~[]T](collection Slice, i int, elements ...T) Slice {
 
 	return append(append(append(output, collection[:i]...), elements...), collection[i:]...)
 }
-
-// CrossJoin calculates the cartesian product of two lists. It returns a list of
-// tuples where the first element includes the elements of the first parameter, and
-// the second element contains the elements of the second parameter.
-
-// It returns an empty list if either, or both parameters are empty
-
-// Play: https://go.dev/play/p/2-DOGciKvAB
-func CrossJoin[T, U any](listOne []T, listTwo []U) [][2]interface{} {
-
-	if len(listOne) == 0 || len(listTwo) == 0 {
-		return make([][2]interface{}, 0)
-	}
-
-	cartesianProduct := make([][2]interface{}, 0, len(listOne)*len(listTwo))
-
-	for _, a := range listOne {
-		for _, b := range listTwo {
-			cartesianProduct = append(cartesianProduct, [2]interface{}{a, b})
-		}
-	}
-
-	return cartesianProduct
-}

slice_test.go

@@ -1046,34 +1046,3 @@ func TestSplice(t *testing.T) {
 	nonempty := Splice(allStrings, 1, "1", "2")
 	is.IsType(nonempty, allStrings, "type preserved")
 }
-
-func TestCrossJoin(t *testing.T) {
-	t.Parallel()
-	is := assert.New(t)
-
-	listOne := []string{"a", "b", "c"}
-	listTwo := []int{1, 2, 3}
-	emptyList := make([][2]any, 0)
-	mixedList := []any{9.6, 4, "foobar"}
-
-	results := CrossJoin(emptyList, listTwo)
-	is.Equal(emptyList, results)
-
-	results = CrossJoin(listOne, emptyList)
-	is.Equal(emptyList, results)
-
-	results = CrossJoin(emptyList, emptyList)
-	is.Equal(emptyList, results)
-
-	results = CrossJoin([]string{"a"}, listTwo)
-	is.Equal([][2]any{{"a", 1}, {"a", 2}, {"a", 3}}, results)
-
-	results = CrossJoin(listOne, []int{1})
-	is.Equal([][2]any{{"a", 1}, {"b", 1}, {"c", 1}}, results)
-
-	results = CrossJoin(listOne, listTwo)
-	is.Equal([][2]any{{"a", 1}, {"a", 2}, {"a", 3}, {"b", 1}, {"b", 2}, {"b", 3}, {"c", 1}, {"c", 2}, {"c", 3}}, results)
-
-	results = CrossJoin(listOne, mixedList)
-	is.Equal([][2]any{{"a", 9.6}, {"a", 4}, {"a", "foobar"}, {"b", 9.6}, {"b", 4}, {"b", "foobar"}, {"c", 9.6}, {"c", 4}, {"c", "foobar"}}, results)
-}