list: add sublist method (#49)

SubList returns a sub list of the original list between the specified fromIndex, inclusive, and toIndex, exclusive.

datastructure/list/list.go

@@ -285,3 +285,11 @@ func (l *List[T]) Intersection(other *List[T]) *List[T] {
 
 	return result
 }
+
+// SubList returns a sub list of the original list between the specified fromIndex, inclusive, and toIndex, exclusive.
+func (l *List[T]) SubList(fromIndex, toIndex int) *List[T] {
+	data := l.data[fromIndex:toIndex]
+	subList := make([]T, len(data))
+	copy(subList, data)
+	return NewList(subList)
+}

datastructure/list/list_test.go

@@ -315,3 +315,19 @@ func TestIntersection(t *testing.T) {
 	list3 := list1.Intersection(list2)
 	assert.Equal(true, expected.Equal(list3))
 }
+
+func TestSubSlice(t *testing.T) {
+	assert := internal.NewAssert(t, "TestSubSlice")
+
+	list := NewList([]int{1, 2, 3, 4, 5, 8})
+	subList := list.SubList(2, 5)
+
+	assert.Equal([]int{3, 4, 5}, subList.Data())
+}
+
+func BenchmarkSubSlice(b *testing.B) {
+	list := NewList([]int{1, 2, 3, 4, 5, 8})
+	for n := 0; n < b.N; n++ {
+		list.SubList(2, 5)
+	}
+}

docs/datastructure/list.md

@@ -46,6 +46,7 @@ import (
 - [Unique](#Unique)
 - [Union](#Union)
 - [Intersection](#Intersection)
+- [SubList](#SubList)
 
 <div STYLE="page-break-after: always;"></div>
 
@@ -791,4 +792,32 @@ func main() {
 
     fmt.Println(li3.Data()) //4
 }
+```
+
+
+
+
+### <span id="SubList">SubList</span>
+<p>SubList returns a sub list of the original list between the specified fromIndex, inclusive, and toIndex, exclusive.</p>
+
+<b>Signature:</b>
+
+```go
+func (l *List[T]) SubList(fromIndex, toIndex int) *List[T] 
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    list "github.com/duke-git/lancet/v2/datastructure/list"
+)
+
+func main() {
+    l := list.NewList([]int{1, 2, 3, 4, 5, 6})
+   
+    fmt.Println(l.SubList(2, 5)) // []int{3, 4, 5}
+}
 ```