diff --git a/datastructure/link/doublylink.go b/datastructure/link/doublylink.go
index b1d322e..173e6a3 100644
--- a/datastructure/link/doublylink.go
+++ b/datastructure/link/doublylink.go
@@ -1,13 +1,12 @@
 package datastructure
 
 import (
-	"errors"
 	"fmt"
 
 	"github.com/duke-git/lancet/v2/datastructure"
 )
 
-// DoublyLink is a linked list. Whose node has a generic Value, Pre pointer points to a previous node of the link, Next pointer points to a next node of the link.
+// DoublyLink is a linked list. Whose node has a generic Value, Pre pointer points to a previous node of the dl, Next pointer points to a next node of the dl.
 type DoublyLink[T any] struct {
 	Head   *datastructure.LinkNode[T]
 	length int
@@ -19,30 +18,30 @@ func NewDoublyLink[T any]() *DoublyLink[T] {
 }
 
 // InsertAtHead insert value into doubly linklist at head index
-func (link *DoublyLink[T]) InsertAtHead(value T) {
+func (dl *DoublyLink[T]) InsertAtHead(value T) {
 	newNode := datastructure.NewLinkNode(value)
-	size := link.Size()
+	size := dl.Size()
 
 	if size == 0 {
-		link.Head = newNode
-		link.length++
+		dl.Head = newNode
+		dl.length++
 		return
 	}
 
-	newNode.Next = link.Head
+	newNode.Next = dl.Head
 	newNode.Pre = nil
 
-	link.Head.Pre = newNode
-	link.Head = newNode
+	dl.Head.Pre = newNode
+	dl.Head = newNode
 
-	link.length++
+	dl.length++
 }
 
 // InsertAtTail insert value into doubly linklist at tail index
-func (link *DoublyLink[T]) InsertAtTail(value T) {
-	current := link.Head
+func (dl *DoublyLink[T]) InsertAtTail(value T) {
+	current := dl.Head
 	if current == nil {
-		link.InsertAtHead(value)
+		dl.InsertAtHead(value)
 		return
 	}
 
@@ -55,28 +54,29 @@ func (link *DoublyLink[T]) InsertAtTail(value T) {
 	newNode.Pre = current
 	current.Next = newNode
 
-	link.length++
+	dl.length++
 }
 
 // InsertAt insert value into doubly linklist at index
-func (link *DoublyLink[T]) InsertAt(index int, value T) error {
-	size := link.length
+// param `index` should between [0, length], if index do not meet the conditions, do nothing
+func (dl *DoublyLink[T]) InsertAt(index int, value T) {
+	size := dl.length
 	if index < 0 || index > size {
-		return errors.New("param index should between 0 and the length of doubly link.")
+		return
 	}
 
 	if index == 0 {
-		link.InsertAtHead(value)
-		return nil
+		dl.InsertAtHead(value)
+		return
 	}
 
 	if index == size {
-		link.InsertAtTail(value)
-		return nil
+		dl.InsertAtTail(value)
+		return
 	}
 
 	i := 0
-	current := link.Head
+	current := dl.Head
 
 	for current != nil {
 		if i == index-1 {
@@ -85,38 +85,36 @@ func (link *DoublyLink[T]) InsertAt(index int, value T) error {
 			newNode.Pre = current
 
 			current.Next = newNode
-			link.length++
+			dl.length++
 
-			return nil
+			return
 		}
 		i++
 		current = current.Next
 	}
-
-	return errors.New("doubly link list no exist")
 }
 
 // DeleteAtHead delete value in doubly linklist at head index
-func (link *DoublyLink[T]) DeleteAtHead() error {
-	if link.Head == nil {
-		return errors.New("doubly link list no exist")
+func (dl *DoublyLink[T]) DeleteAtHead() {
+	if dl.Head == nil {
+		return
 	}
-	current := link.Head
-	link.Head = current.Next
-	link.Head.Pre = nil
-	link.length--
 
-	return nil
+	current := dl.Head
+	dl.Head = current.Next
+	dl.Head.Pre = nil
+	dl.length--
 }
 
-// DeleteAtTail delete value in doubly linklist at tail index
-func (link *DoublyLink[T]) DeleteAtTail() error {
-	if link.Head == nil {
-		return errors.New("doubly link list no exist")
+// DeleteAtTail delete value in doubly linklist at tail
+func (dl *DoublyLink[T]) DeleteAtTail() {
+	if dl.Head == nil {
+		return
 	}
-	current := link.Head
+
+	current := dl.Head
 	if current.Next == nil {
-		return link.DeleteAtHead()
+		dl.DeleteAtHead()
 	}
 
 	for current.Next.Next != nil {
@@ -124,45 +122,44 @@ func (link *DoublyLink[T]) DeleteAtTail() error {
 	}
 
 	current.Next = nil
-	link.length--
-	return nil
+	dl.length--
 }
 
 // DeleteAt delete value in doubly linklist at index
-func (link *DoublyLink[T]) DeleteAt(index int) error {
-	if link.Head == nil {
-		return errors.New("doubly link list no exist")
+// param `index` should be [0, len(DoublyLink)-1]
+func (dl *DoublyLink[T]) DeleteAt(index int) {
+	if dl.Head == nil {
+		return
 	}
-	current := link.Head
+
+	current := dl.Head
 	if current.Next == nil || index == 0 {
-		return link.DeleteAtHead()
+		dl.DeleteAtHead()
 	}
 
-	if index == link.length-1 {
-		return link.DeleteAtTail()
+	if index == dl.length-1 {
+		dl.DeleteAtTail()
 	}
 
-	if index < 0 || index > link.length-1 {
-		return errors.New("param index should between 0 and link size -1.")
+	if index < 0 || index > dl.length-1 {
+		return
 	}
 
 	i := 0
 	for current != nil {
 		if i == index-1 {
 			current.Next = current.Next.Next
-			link.length--
-			return nil
+			dl.length--
+			return
 		}
 		i++
 		current = current.Next
 	}
-
-	return errors.New("delete error")
 }
 
 // Reverse the linked list
-func (link *DoublyLink[T]) Reverse() {
-	current := link.Head
+func (dl *DoublyLink[T]) Reverse() {
+	current := dl.Head
 	var temp *datastructure.LinkNode[T]
 
 	for current != nil {
@@ -173,20 +170,20 @@ func (link *DoublyLink[T]) Reverse() {
 	}
 
 	if temp != nil {
-		link.Head = temp.Pre
+		dl.Head = temp.Pre
 	}
 }
 
 // GetMiddleNode return node at middle index of linked list
-func (link *DoublyLink[T]) GetMiddleNode() *datastructure.LinkNode[T] {
-	if link.Head == nil {
+func (dl *DoublyLink[T]) GetMiddleNode() *datastructure.LinkNode[T] {
+	if dl.Head == nil {
 		return nil
 	}
-	if link.Head.Next == nil {
-		return link.Head
+	if dl.Head.Next == nil {
+		return dl.Head
 	}
-	fast := link.Head
-	slow := link.Head
+	fast := dl.Head
+	slow := dl.Head
 
 	for fast != nil {
 		fast = fast.Next
@@ -202,14 +199,14 @@ func (link *DoublyLink[T]) GetMiddleNode() *datastructure.LinkNode[T] {
 }
 
 // Size return the count of doubly linked list
-func (link *DoublyLink[T]) Size() int {
-	return link.length
+func (dl *DoublyLink[T]) Size() int {
+	return dl.length
 }
 
 // Values return slice of all doubly linklist node value
-func (link *DoublyLink[T]) Values() []T {
+func (dl *DoublyLink[T]) Values() []T {
 	result := []T{}
-	current := link.Head
+	current := dl.Head
 	for current != nil {
 		result = append(result, current.Value)
 		current = current.Next
@@ -218,8 +215,8 @@ func (link *DoublyLink[T]) Values() []T {
 }
 
 // Print all nodes info of a linked list
-func (link *DoublyLink[T]) Print() {
-	current := link.Head
+func (dl *DoublyLink[T]) Print() {
+	current := dl.Head
 	info := "[ "
 	for current != nil {
 		info += fmt.Sprintf("%+v, ", current)
@@ -229,13 +226,13 @@ func (link *DoublyLink[T]) Print() {
 	fmt.Println(info)
 }
 
-// IsEmpty checks if link is empty or not
-func (link *DoublyLink[T]) IsEmpty() bool {
-	return link.length == 0
+// IsEmpty checks if dl is empty or not
+func (dl *DoublyLink[T]) IsEmpty() bool {
+	return dl.length == 0
 }
 
 // Clear all nodes in doubly linklist
-func (link *DoublyLink[T]) Clear() {
-	link.Head = nil
-	link.length = 0
+func (dl *DoublyLink[T]) Clear() {
+	dl.Head = nil
+	dl.length = 0
 }
diff --git a/datastructure/link/doublylink_test.go b/datastructure/link/doublylink_test.go
index 83998ff..6441ef4 100644
--- a/datastructure/link/doublylink_test.go
+++ b/datastructure/link/doublylink_test.go
@@ -41,29 +41,24 @@ func TestDoublyLink_InsertAt(t *testing.T) {
 
 	link := NewDoublyLink[int]()
 
-	err := link.InsertAt(1, 1)
-	assert.IsNotNil(err)
+	link.InsertAt(1, 1) //do nothing
 
 	link.InsertAt(0, 1)
 	link.InsertAt(1, 2)
 	link.InsertAt(2, 4)
 	link.InsertAt(2, 3)
 
-	link.Print()
-
 	expected := []int{1, 2, 3, 4}
 	values := link.Values()
 
 	assert.Equal(expected, values)
-
 }
 
 func TestDoublyLink_DeleteAtHead(t *testing.T) {
 	assert := internal.NewAssert(t, "TestDoublyLink_DeleteAtHead")
 
 	link := NewDoublyLink[int]()
-	err := link.DeleteAtHead()
-	assert.IsNotNil(err)
+	link.DeleteAtHead()
 
 	link.InsertAtTail(1)
 	link.InsertAtTail(2)
@@ -71,7 +66,6 @@ func TestDoublyLink_DeleteAtHead(t *testing.T) {
 	link.InsertAtTail(4)
 
 	link.DeleteAtHead()
-	link.Print()
 
 	expected := []int{2, 3, 4}
 	values := link.Values()
@@ -83,8 +77,7 @@ func TestDoublyLink_DeleteAtTail(t *testing.T) {
 	assert := internal.NewAssert(t, "TestDoublyLink_DeleteAtTail")
 
 	link := NewDoublyLink[int]()
-	err := link.DeleteAtTail()
-	assert.IsNotNil(err)
+	link.DeleteAtTail()
 
 	link.InsertAtTail(1)
 	link.InsertAtTail(2)
@@ -92,7 +85,6 @@ func TestDoublyLink_DeleteAtTail(t *testing.T) {
 	link.InsertAtTail(4)
 
 	link.DeleteAtTail()
-	link.Print()
 
 	expected := []int{1, 2, 3}
 	values := link.Values()
@@ -104,8 +96,7 @@ func TestDoublyLink_DeleteAt(t *testing.T) {
 	assert := internal.NewAssert(t, "TestDoublyLink_DeleteAt")
 
 	link := NewDoublyLink[int]()
-	err := link.DeleteAt(0)
-	assert.IsNotNil(err)
+	link.DeleteAt(0)
 
 	link.InsertAtTail(1)
 	link.InsertAtTail(2)
@@ -113,11 +104,7 @@ func TestDoublyLink_DeleteAt(t *testing.T) {
 	link.InsertAtTail(4)
 	link.InsertAtTail(5)
 
-	err = link.DeleteAt(5)
-	assert.IsNotNil(err)
-
-	err = link.DeleteAt(0)
-	assert.IsNil(err)
+	link.DeleteAt(0)
 	assert.Equal([]int{2, 3, 4, 5}, link.Values())
 
 	link.DeleteAt(3)
diff --git a/datastructure/link/singlylink.go b/datastructure/link/singlylink.go
index b4a3791..555d68e 100644
--- a/datastructure/link/singlylink.go
+++ b/datastructure/link/singlylink.go
@@ -1,14 +1,13 @@
 package datastructure
 
 import (
-	"errors"
 	"fmt"
 	"reflect"
 
 	"github.com/duke-git/lancet/v2/datastructure"
 )
 
-// SinglyLink is a linked list. Whose node has a Value generics and Next pointer points to a next node of the link.
+// SinglyLink is a linked list. Whose node has a Value generics and Next pointer points to a next node of the sl.
 type SinglyLink[T any] struct {
 	Head   *datastructure.LinkNode[T]
 	length int
@@ -20,18 +19,18 @@ func NewSinglyLink[T any]() *SinglyLink[T] {
 }
 
 // InsertAtHead insert value into singly linklist at head index
-func (link *SinglyLink[T]) InsertAtHead(value T) {
+func (sl *SinglyLink[T]) InsertAtHead(value T) {
 	newNode := datastructure.NewLinkNode(value)
-	newNode.Next = link.Head
-	link.Head = newNode
-	link.length++
+	newNode.Next = sl.Head
+	sl.Head = newNode
+	sl.length++
 }
 
 // InsertAtTail insert value into singly linklist at tail index
-func (link *SinglyLink[T]) InsertAtTail(value T) {
-	current := link.Head
+func (sl *SinglyLink[T]) InsertAtTail(value T) {
+	current := sl.Head
 	if current == nil {
-		link.InsertAtHead(value)
+		sl.InsertAtHead(value)
 		return
 	}
 
@@ -43,65 +42,65 @@ func (link *SinglyLink[T]) InsertAtTail(value T) {
 	newNode.Next = nil
 	current.Next = newNode
 
-	link.length++
+	sl.length++
 }
 
 // InsertAt insert value into singly linklist at index
-func (link *SinglyLink[T]) InsertAt(index int, value T) error {
-	size := link.length
+// param `index` should between [0, len(SinglyLink)], if index do not meet the conditions, do nothing
+func (sl *SinglyLink[T]) InsertAt(index int, value T) {
+	size := sl.length
 	if index < 0 || index > size {
-		return errors.New("param index should between 0 and the length of singly link.")
+		return
 	}
 
 	if index == 0 {
-		link.InsertAtHead(value)
-		return nil
+		sl.InsertAtHead(value)
+		return
 	}
 
 	if index == size {
-		link.InsertAtTail(value)
-		return nil
+		sl.InsertAtTail(value)
+		return
 	}
 
 	i := 0
-	current := link.Head
+	current := sl.Head
 
 	for current != nil {
 		if i == index-1 {
 			newNode := datastructure.NewLinkNode(value)
 			newNode.Next = current.Next
 			current.Next = newNode
-			link.length++
-
-			return nil
+			sl.length++
+			return
 		}
 		i++
 		current = current.Next
 	}
 
-	return errors.New("singly link list no exist")
+	return
 }
 
 // DeleteAtHead delete value in singly linklist at head index
-func (link *SinglyLink[T]) DeleteAtHead() error {
-	if link.Head == nil {
-		return errors.New("singly link list no exist")
+func (sl *SinglyLink[T]) DeleteAtHead() {
+	if sl.Head == nil {
+		return
 	}
-	current := link.Head
-	link.Head = current.Next
-	link.length--
 
-	return nil
+	current := sl.Head
+	sl.Head = current.Next
+	sl.length--
 }
 
-// DeleteAtTail delete value in singly linklist at tail index
-func (link *SinglyLink[T]) DeleteAtTail() error {
-	if link.Head == nil {
-		return errors.New("singly link list no exist")
+// DeleteAtTail delete value in singly linklist at tail
+func (sl *SinglyLink[T]) DeleteAtTail() {
+	if sl.Head == nil {
+		return
 	}
-	current := link.Head
+
+	current := sl.Head
 	if current.Next == nil {
-		return link.DeleteAtHead()
+		sl.DeleteAtHead()
 	}
 
 	for current.Next.Next != nil {
@@ -109,68 +108,66 @@ func (link *SinglyLink[T]) DeleteAtTail() error {
 	}
 
 	current.Next = nil
-	link.length--
-	return nil
+	sl.length--
 }
 
 // DeleteAt delete value in singly linklist at index
-func (link *SinglyLink[T]) DeleteAt(index int) error {
-	if link.Head == nil {
-		return errors.New("singly link list no exist")
+// param `index` should be [0, len(SinglyLink)-1]
+func (sl *SinglyLink[T]) DeleteAt(index int) {
+	if sl.Head == nil {
+		return
 	}
-	current := link.Head
+	current := sl.Head
 	if current.Next == nil || index == 0 {
-		return link.DeleteAtHead()
+		sl.DeleteAtHead()
 	}
 
-	if index == link.length-1 {
-		return link.DeleteAtTail()
+	if index == sl.length-1 {
+		sl.DeleteAtTail()
 	}
 
-	if index < 0 || index > link.length-1 {
-		return errors.New("param index should between 0 and link size -1.")
+	if index < 0 || index > sl.length-1 {
+		return
 	}
 
 	i := 0
 	for current != nil {
 		if i == index-1 {
 			current.Next = current.Next.Next
-			link.length--
-			return nil
+			sl.length--
+			return
 		}
 		i++
 		current = current.Next
 	}
-
-	return errors.New("delete error")
 }
 
 // DeleteValue delete value in singly linklist
-func (link *SinglyLink[T]) DeleteValue(value T) {
-	if link.Head == nil {
+func (sl *SinglyLink[T]) DeleteValue(value T) {
+	if sl.Head == nil {
 		return
 	}
 	dummyHead := datastructure.NewLinkNode(value)
-	dummyHead.Next = link.Head
+	dummyHead.Next = sl.Head
 	current := dummyHead
 
 	for current.Next != nil {
 		if reflect.DeepEqual(current.Next.Value, value) {
 			current.Next = current.Next.Next
-			link.length--
+			sl.length--
 		} else {
 			current = current.Next
 		}
 	}
 
-	link.Head = dummyHead.Next
+	sl.Head = dummyHead.Next
 }
 
 // Reverse the linked list
-func (link *SinglyLink[T]) Reverse() {
+func (sl *SinglyLink[T]) Reverse() {
 	var pre, next *datastructure.LinkNode[T]
 
-	current := link.Head
+	current := sl.Head
 
 	for current != nil {
 		next = current.Next
@@ -179,19 +176,19 @@ func (link *SinglyLink[T]) Reverse() {
 		current = next
 	}
 
-	link.Head = pre
+	sl.Head = pre
 }
 
 // GetMiddleNode return node at middle index of linked list
-func (link *SinglyLink[T]) GetMiddleNode() *datastructure.LinkNode[T] {
-	if link.Head == nil {
+func (sl *SinglyLink[T]) GetMiddleNode() *datastructure.LinkNode[T] {
+	if sl.Head == nil {
 		return nil
 	}
-	if link.Head.Next == nil {
-		return link.Head
+	if sl.Head.Next == nil {
+		return sl.Head
 	}
-	fast := link.Head
-	slow := link.Head
+	fast := sl.Head
+	slow := sl.Head
 
 	for fast != nil {
 		fast = fast.Next
@@ -207,14 +204,14 @@ func (link *SinglyLink[T]) GetMiddleNode() *datastructure.LinkNode[T] {
 }
 
 // Size return the count of singly linked list
-func (link *SinglyLink[T]) Size() int {
-	return link.length
+func (sl *SinglyLink[T]) Size() int {
+	return sl.length
 }
 
 // Values return slice of all singly linklist node value
-func (link *SinglyLink[T]) Values() []T {
+func (sl *SinglyLink[T]) Values() []T {
 	result := []T{}
-	current := link.Head
+	current := sl.Head
 	for current != nil {
 		result = append(result, current.Value)
 		current = current.Next
@@ -222,20 +219,20 @@ func (link *SinglyLink[T]) Values() []T {
 	return result
 }
 
-// IsEmpty checks if link is empty or not
-func (link *SinglyLink[T]) IsEmpty() bool {
-	return link.length == 0
+// IsEmpty checks if sl is empty or not
+func (sl *SinglyLink[T]) IsEmpty() bool {
+	return sl.length == 0
 }
 
 // Clear all the node in singly linklist
-func (link *SinglyLink[T]) Clear() {
-	link.Head = nil
-	link.length = 0
+func (sl *SinglyLink[T]) Clear() {
+	sl.Head = nil
+	sl.length = 0
 }
 
 // Print all nodes info of a linked list
-func (link *SinglyLink[T]) Print() {
-	current := link.Head
+func (sl *SinglyLink[T]) Print() {
+	current := sl.Head
 	info := "[ "
 	for current != nil {
 		info += fmt.Sprintf("%+v, ", current)
diff --git a/datastructure/link/singlylink_test.go b/datastructure/link/singlylink_test.go
index c2cbee4..72b9012 100644
--- a/datastructure/link/singlylink_test.go
+++ b/datastructure/link/singlylink_test.go
@@ -41,25 +41,12 @@ func TestSinglyLink_InsertAt(t *testing.T) {
 
 	link := NewSinglyLink[int]()
 
-	err := link.InsertAt(1, 1)
-	assert.IsNotNil(err)
+	link.InsertAt(1, 1) //do nothing
 
-	err = link.InsertAt(0, 1)
-	if err != nil {
-		t.FailNow()
-	}
-	err = link.InsertAt(1, 2)
-	if err != nil {
-		t.FailNow()
-	}
-	err = link.InsertAt(2, 4)
-	if err != nil {
-		t.FailNow()
-	}
-	err = link.InsertAt(2, 3)
-	if err != nil {
-		t.FailNow()
-	}
+	link.InsertAt(0, 1)
+	link.InsertAt(1, 2)
+	link.InsertAt(2, 4)
+	link.InsertAt(2, 3)
 
 	link.Print()
 
@@ -73,8 +60,8 @@ func TestSinglyLink_DeleteAtHead(t *testing.T) {
 	assert := internal.NewAssert(t, "TestSinglyLink_DeleteAtHead")
 
 	link := NewSinglyLink[int]()
-	err := link.DeleteAtHead()
-	assert.IsNotNil(err)
+
+	link.DeleteAtHead()
 
 	link.InsertAtTail(1)
 	link.InsertAtTail(2)
@@ -94,8 +81,6 @@ func TestSinglyLink_DeleteAtTail(t *testing.T) {
 	assert := internal.NewAssert(t, "TestSinglyLink_DeleteAtTail")
 
 	link := NewSinglyLink[int]()
-	err := link.DeleteAtTail()
-	assert.IsNotNil(err)
 
 	link.InsertAtTail(1)
 	link.InsertAtTail(2)
@@ -103,7 +88,6 @@ func TestSinglyLink_DeleteAtTail(t *testing.T) {
 	link.InsertAtTail(4)
 
 	link.DeleteAtTail()
-	link.Print()
 
 	expected := []int{1, 2, 3}
 	values := link.Values()
@@ -133,8 +117,6 @@ func TestSinglyLink_DeleteAt(t *testing.T) {
 	assert := internal.NewAssert(t, "TestSinglyLink_DeleteAt")
 
 	link := NewSinglyLink[int]()
-	err := link.DeleteAt(0)
-	assert.IsNotNil(err)
 
 	link.InsertAtTail(1)
 	link.InsertAtTail(2)
@@ -142,11 +124,7 @@ func TestSinglyLink_DeleteAt(t *testing.T) {
 	link.InsertAtTail(4)
 	link.InsertAtTail(5)
 
-	err = link.DeleteAt(5)
-	assert.IsNotNil(err)
-
-	err = link.DeleteAt(0)
-	assert.IsNil(err)
+	link.DeleteAt(0)
 	assert.Equal([]int{2, 3, 4, 5}, link.Values())
 
 	link.DeleteAt(3)
diff --git a/docs/datastructure/linklist.md b/docs/datastructure/linklist.md
index b932f72..174ccff 100644
--- a/docs/datastructure/linklist.md
+++ b/docs/datastructure/linklist.md
@@ -132,12 +132,12 @@ func main() {
 
 
 ### <span id="SinglyLink_InsertAt">InsertAt</span>
-<p>Insert value into singly linklist at index, index shoud be great or equal 0 and less or equal number of link nodes</p>
+<p>Insert value into singly linklist at index, param `index` should between [0, len(SinglyLink)], if index do not meet the conditions, do nothing</p>
 
 <b>Signature:</b>
 
 ```go
-func (link *SinglyLink[T]) InsertAt(index int, value T) error
+func (link *SinglyLink[T]) InsertAt(index int, value T)
 ```
 <b>Example:</b>
 
@@ -152,6 +152,8 @@ import (
 func main() {
     lk := link.NewSinglyLink[int]()
 
+    lk.InsertAt(1, 1) //do nothing
+    
     lk.InsertAt(0, 1)
     lk.InsertAt(1, 2)
     lk.InsertAt(2, 3)
@@ -228,12 +230,12 @@ func main() {
 
 
 ### <span id="SinglyLink_DeleteAt">DeleteAt</span>
-<p>Delete value at specific index, index shoud be great or equal 0 and less or less than number of link nodes - 1</p>
+<p>Delete value at specific index, param `index` should be [0, len(SinglyLink)-1]</p>
 
 <b>Signature:</b>
 
 ```go
-func (link *SinglyLink[T]) DeleteAt(index int) error
+func (link *SinglyLink[T]) DeleteAt(index int)
 ```
 <b>Example:</b>
 
@@ -253,9 +255,8 @@ func main() {
     lk.InsertAtTail(3)
     lk.InsertAtTail(4)
 
-    err := lk.DeleteAt(3)
+    lk.DeleteAt(3)
 
-    fmt.Println(err) //nil
     fmt.Println(lk.Values()) //[]int{1, 2, 3}
 }
 ```
@@ -268,7 +269,7 @@ func main() {
 <b>Signature:</b>
 
 ```go
-func (link *SinglyLink[T]) DeleteAtHead() error
+func (link *SinglyLink[T]) DeleteAtHead()
 ```
 <b>Example:</b>
 
@@ -288,9 +289,8 @@ func main() {
     lk.InsertAtTail(3)
     lk.InsertAtTail(4)
 
-    err := lk.DeleteAtHead()
+    lk.DeleteAtHead()
     
-    fmt.Println(err) //nil
     fmt.Println(lk.Values()) //[]int{2, 3, 4}
 }
 ```
@@ -304,7 +304,7 @@ func main() {
 <b>Signature:</b>
 
 ```go
-func (link *SinglyLink[T]) DeleteAtTail() error
+func (link *SinglyLink[T]) DeleteAtTail()
 ```
 <b>Example:</b>
 
@@ -323,9 +323,8 @@ func main() {
     lk.InsertAtTail(2)
     lk.InsertAtTail(3)
 
-    err := lk.DeleteAtTail()
+    lk.DeleteAtTail()
     
-    fmt.Println(err) //nil
     fmt.Println(lk.Values()) //[]int{1, 2}
 }
 ```
@@ -628,12 +627,12 @@ func main() {
 
 
 ### <span id="DoublyLink_InsertAt">InsertAt</span>
-<p>Insert value into doubly linklist at index, index shoud be great or equal 0 and less or equal number of link nodes</p>
+<p>Insert value into doubly linklist at index, param `index` should between [0, len(DoublyLink)], if index do not meet the conditions, do nothing</p>
 
 <b>Signature:</b>
 
 ```go
-func (link *DoublyLink[T]) InsertAt(index int, value T) error
+func (link *DoublyLink[T]) InsertAt(index int, value T)
 ```
 <b>Example:</b>
 
@@ -648,6 +647,8 @@ import (
 func main() {
     lk := link.NewDoublyLink[int]()
 
+    lk.InsertAt(1, 1) //do nothing
+
     lk.InsertAt(0, 1)
     lk.InsertAt(1, 2)
     lk.InsertAt(2, 3)
@@ -724,12 +725,12 @@ func main() {
 
 
 ### <span id="DoublyLink_DeleteAt">DeleteAt</span>
-<p>Delete value at specific index, index shoud be great or equal 0 and less or less than number of link nodes - 1</p>
+<p>Delete value at specific index, param `index` should be [0, len(DoublyLink)-1]</p>
 
 <b>Signature:</b>
 
 ```go
-func (link *DoublyLink[T]) DeleteAt(index int) error
+func (link *DoublyLink[T]) DeleteAt(index int)
 ```
 <b>Example:</b>
 
@@ -749,9 +750,8 @@ func main() {
     lk.InsertAtTail(3)
     lk.InsertAtTail(4)
 
-    err := lk.DeleteAt(3)
+    lk.DeleteAt(3)
 
-    fmt.Println(err) //nil
     fmt.Println(lk.Values()) //[]int{1, 2, 3}
 }
 ```
@@ -764,7 +764,7 @@ func main() {
 <b>Signature:</b>
 
 ```go
-func (link *DoublyLink[T]) DeleteAtHead() error
+func (link *DoublyLink[T]) DeleteAtHead()
 ```
 <b>Example:</b>
 
@@ -784,9 +784,8 @@ func main() {
     lk.InsertAtTail(3)
     lk.InsertAtTail(4)
 
-    err := lk.DeleteAtHead()
+    lk.DeleteAtHead()
     
-    fmt.Println(err) //nil
     fmt.Println(lk.Values()) //[]int{2, 3, 4}
 }
 ```
diff --git a/docs/datastructure/linklist_zh-CN.md b/docs/datastructure/linklist_zh-CN.md
index 25e687f..f7bc2e4 100644
--- a/docs/datastructure/linklist_zh-CN.md
+++ b/docs/datastructure/linklist_zh-CN.md
@@ -132,12 +132,12 @@ func main() {
 
 
 ### <span id="SinglyLink_InsertAt">InsertAt</span>
-<p>将值插入到索引处的链表中，索引应大于或等于 0 且小于或等于链表节点数</p>
+<p>将值插入到索引处的链表中，索引应大于或等于0且小于或等于链表节点数</p>
 
 <b>函数签名:</b>
 
 ```go
-func (link *SinglyLink[T]) InsertAt(index int, value T) error
+func (link *SinglyLink[T]) InsertAt(index int, value T)
 ```
 <b>例子:</b>
 
@@ -152,6 +152,8 @@ import (
 func main() {
     lk := link.NewSinglyLink[int]()
 
+    lk.InsertAt(1, 1) //do nothing
+
     lk.InsertAt(0, 1)
     lk.InsertAt(1, 2)
     lk.InsertAt(2, 3)
@@ -228,12 +230,12 @@ func main() {
 
 
 ### <span id="SinglyLink_DeleteAt">DeleteAt</span>
-<p>删除特定索引处的值，索引应大于或等于0且小于或等于链接节点数 - 1</p>
+<p>删除特定索引处的值，索引应大于或等于0且小于或等于链接节点数-1</p>
 
 <b>函数签名:</b>
 
 ```go
-func (link *SinglyLink[T]) DeleteAt(index int) error
+func (link *SinglyLink[T]) DeleteAt(index int)
 ```
 <b>例子:</b>
 
@@ -253,9 +255,8 @@ func main() {
     lk.InsertAtTail(3)
     lk.InsertAtTail(4)
 
-    err := lk.DeleteAt(3)
+    lk.DeleteAt(3)
 
-    fmt.Println(err) //nil
     fmt.Println(lk.Values()) //[]int{1, 2, 3}
 }
 ```
@@ -268,7 +269,7 @@ func main() {
 <b>函数签名:</b>
 
 ```go
-func (link *SinglyLink[T]) DeleteAtHead() error
+func (link *SinglyLink[T]) DeleteAtHead()
 ```
 <b>例子:</b>
 
@@ -288,9 +289,8 @@ func main() {
     lk.InsertAtTail(3)
     lk.InsertAtTail(4)
 
-    err := lk.DeleteAtHead()
+    lk.DeleteAtHead()
     
-    fmt.Println(err) //nil
     fmt.Println(lk.Values()) //[]int{2, 3, 4}
 }
 ```
@@ -304,7 +304,7 @@ func main() {
 <b>函数签名:</b>
 
 ```go
-func (link *SinglyLink[T]) DeleteAtTail() error
+func (link *SinglyLink[T]) DeleteAtTail()
 ```
 <b>例子:</b>
 
@@ -323,9 +323,8 @@ func main() {
     lk.InsertAtTail(2)
     lk.InsertAtTail(3)
 
-    err := lk.DeleteAtTail()
+    lk.DeleteAtTail()
     
-    fmt.Println(err) //nil
     fmt.Println(lk.Values()) //[]int{1, 2}
 }
 ```
@@ -628,12 +627,12 @@ func main() {
 
 
 ### <span id="DoublyLink_InsertAt">InsertAt</span>
-<p>将值插入到索引处的链表中，索引应大于或等于 0 且小于或等于链表节点数</p>
+<p>将值插入到索引处的链表中，索引应大于或等于0且小于或等于链表节点数</p>
 
 <b>函数签名:</b>
 
 ```go
-func (link *DoublyLink[T]) InsertAt(index int, value T) error
+func (link *DoublyLink[T]) InsertAt(index int, value T)
 ```
 <b>例子:</b>
 
@@ -648,6 +647,8 @@ import (
 func main() {
     lk := link.NewDoublyLink[int]()
 
+    lk.InsertAt(1, 1) //do nothing
+
     lk.InsertAt(0, 1)
     lk.InsertAt(1, 2)
     lk.InsertAt(2, 3)
@@ -724,12 +725,12 @@ func main() {
 
 
 ### <span id="DoublyLink_DeleteAt">DeleteAt</span>
-<p>删除特定索引处的值，索引应大于或等于0且小于或等于链接节点数 - 1</p>
+<p>删除特定索引处的值，索引应大于或等于0且小于或等于链接节点数-1</p>
 
 <b>函数签名:</b>
 
 ```go
-func (link *DoublyLink[T]) DeleteAt(index int) error
+func (link *DoublyLink[T]) DeleteAt(index int)
 ```
 <b>例子:</b>
 
@@ -749,9 +750,8 @@ func main() {
     lk.InsertAtTail(3)
     lk.InsertAtTail(4)
 
-    err := lk.DeleteAt(3)
+    lk.DeleteAt(3)
 
-    fmt.Println(err) //nil
     fmt.Println(lk.Values()) //[]int{1, 2, 3}
 }
 ```
@@ -764,7 +764,7 @@ func main() {
 <b>函数签名:</b>
 
 ```go
-func (link *DoublyLink[T]) DeleteAtHead() error
+func (link *DoublyLink[T]) DeleteAtHead()
 ```
 <b>例子:</b>
 
@@ -784,9 +784,8 @@ func main() {
     lk.InsertAtTail(3)
     lk.InsertAtTail(4)
 
-    err := lk.DeleteAtHead()
+    lk.DeleteAtHead()
     
-    fmt.Println(err) //nil
     fmt.Println(lk.Values()) //[]int{2, 3, 4}
 }
 ```
@@ -800,7 +799,7 @@ func main() {
 <b>函数签名:</b>
 
 ```go
-func (link *DoublyLink[T]) DeleteAtTail() error
+func (link *DoublyLink[T]) DeleteAtTail()
 ```
 <b>例子:</b>
 
@@ -819,9 +818,8 @@ func main() {
     lk.InsertAtTail(2)
     lk.InsertAtTail(3)
 
-    err := lk.DeleteAtTail()
+    lk.DeleteAtTail()
     
-    fmt.Println(err) //nil
     fmt.Println(lk.Values()) //[]int{1, 2}
 }
 ```