Add Tail and Initial implementations (closes #23 and #17)

scan.go

@@ -150,3 +150,43 @@ func Last(arr interface{}) interface{} {
 
  panic(fmt.Sprintf("Type %s is not supported by Last", valueType.String()))
 }
+
+// Initial gets all but the last element of array.
+func Initial(arr interface{}) interface{} {
+ value := redirectValue(reflect.ValueOf(arr))
+ valueType := value.Type()
+
+ kind := value.Kind()
+
+ if kind == reflect.Array || kind == reflect.Slice {
+ length := value.Len()
+
+ if length <= 1 {
+ return arr
+ }
+
+ return value.Slice(0, length-1).Interface()
+ }
+
+ panic(fmt.Sprintf("Type %s is not supported by Initial", valueType.String()))
+}
+
+// Tail gets all but the last element of array.
+func Tail(arr interface{}) interface{} {
+ value := redirectValue(reflect.ValueOf(arr))
+ valueType := value.Type()
+
+ kind := value.Kind()
+
+ if kind == reflect.Array || kind == reflect.Slice {
+ length := value.Len()
+
+ if length <= 1 {
+ return arr
+ }
+
+ return value.Slice(1, length).Interface()
+ }
+
+ panic(fmt.Sprintf("Type %s is not supported by Initial", valueType.String()))
+}

scan_test.go

@@ -67,3 +67,15 @@ func TestLast(t *testing.T) {
 
  is.Equal(Last([]int{1, 2, 3, 4}), 4)
 }
+
+func TestTail(t *testing.T) {
+ is := assert.New(t)
+
+ is.Equal(Tail([]int{1, 2, 3, 4}), []int{2, 3, 4})
+}
+
+func TestInitial(t *testing.T) {
+ is := assert.New(t)
+
+ is.Equal(Initial([]int{1, 2, 3, 4}), []int{1, 2, 3})
+}