单链表各类基本运算代码

单链表是一种基础的数据结构，其节点包含数据和指向下一个节点的指针。以下是单链表的一些常见操作的简单代码示例，假设我们有一个Node类表示链表节点：

1. **创建链表头节点**:

class Node:
    def __init__(self, data):
        self.data = data
        self.next = None

# 创建一个空链表
head = Node(None)

2. **添加新元素（在链表尾部）**:

def append(head, data):
    new_node = Node(data)
    if head is None:
        head = new_node
    else:
        current = head
        while current.next is not None:
            current = current.next
        current.next = new_node

3. **删除元素（指定值）**:

def delete(head, value):
    if head is None or head.data == value:
        head = head.next
        return

    previous = head
    current = head.next
    while current is not None:
        if current.data == value:
            previous.next = current.next
            break
        previous = current
        current = current.next

4. **遍历链表**:

def traverse(head):
    current = head
    while current is not None:
        print(current.data, end=" -> ")
        current = current.next
    print("None")

5. **查找元素**:

def search(head, value):
    current = head
    while current is not None:
        if current.data == value:
            return True
        current = current.next
    return False