Add slice Splice an element or multiple elements at index i.

README.md

@@ -118,6 +118,7 @@ Supported helpers for slices:
 - [Compact](#compact)
 - [IsSorted](#issorted)
 - [IsSortedByKey](#issortedbykey)
+- [Splice](#Splice)
 
 Supported helpers for maps:
 
@@ -980,6 +981,17 @@ slice := lo.IsSortedByKey([]string{"a", "bb", "ccc"}, func(s string) int {
 
 [[play](https://go.dev/play/p/wiG6XyBBu49)]
 
+### Splice
+
+Insert multiple elements at index i.
+
+```go
+result := lo.Splice([]string{"a", "d"}, 1, "b", "c")
+// []string{"a", "b", "c", "d"}
+```
+
+[[play](https://go.dev/play/p/G5_GhkeSUBA)]
+
 ### Keys
 
 Creates an array of the map keys.

slice.go

@@ -625,3 +625,15 @@ func IsSortedByKey[T any, K constraints.Ordered](collection []T, iteratee func(i
 
 	return true
 }
+
+// Play: https://go.dev/play/p/G5_GhkeSUBA
+func Splice[T any](collection []T, i int, elements ...T) []T {
+	if i < 0 || i > len(collection) {
+		panic("index out of bounds")
+	}
+	if len(elements) == 0 {
+		return collection
+	}
+
+	return append(append(collection[:i], elements...), collection[i:]...)
+}

slice_test.go

@@ -801,3 +801,16 @@ func TestIsSortedByKey(t *testing.T) {
 		return ret
 	}))
 }
+
+func TestInsertSlice(t *testing.T) {
+	t.Parallel()
+	is := assert.New(t)
+
+	inserts := Splice([]string{"a", "d"}, 1, "b", "c")
+	is.Equal(inserts, []string{"a", "b", "c", "d"})
+	is.True(len(inserts) == 4 && inserts[1] == "b" && inserts[2] == "c")
+
+	inserti := Splice([]int{1, 4}, 1, 2, 3)
+	is.Equal(inserti, []int{1, 2, 3, 4})
+	is.True(len(inserti) == 4 && inserti[1] == 2 && inserti[2] == 3)
+}