python--自己实现的单链表常用功能

最近一个月，就耗在这上面吧。

很有收获的。

# coding = utf-8

# 单向链表
class Node:

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

    def get_data(self):
        return self.data

    def set_data(self, new_data):
        self.data = new_data

    def get_next(self):
        return self.next

    def set_next(self, new_next):
        self.next = new_next

class SingleList:

    def __init__(self):
        self.head = None

    # 作头插入时，需要要注意插入顺序，
    # 先将节点的netxt设为head，然后，再将节点设为Head。
    # 总之。要注意不要丢失next。
    def add(self, item):
        temp = Node(item)
        temp.set_next(self.head)
        self.head = temp

    # 作尾插入时，需要先判断是否为空列表。因为空列表时，没有next。
    # 为空列表时，尾插入和头插入代码相同。
    # 当不为空时，需要循环到底，再作插入处理
    def append(self, item):
        temp = Node(item)
        if self.is_empty():
            temp.set_next(self.head)
            self.head = temp
        else:
            current = self.head
            while current.get_next() is not None:
                current = current.get_next()
            current.set_next(temp)

    # 指定位置插入节点
    def insert(self, pos, item):
        # 相当于头插入
        if pos <= 0:
            self.add(item)
        # 相当于尾插入
        elif pos >= self.size():
            self.append(item)
        else:
            temp = Node(item)
            count = 0
            current = self.head
            # 先将游标指到要插入位置
            while count < pos - 1:
                count += 1
                current = current.get_next()
            # 先将节点插入游标下一节点，再将当前游标指向节点
            temp.set_next(current.get_next())
            current.set_next(temp)

    # 删除指定节点数据
    def remove(self, item):
        previous = None
        current = self.head
        while current is not None:
            if current.get_data() == item:
                # 在找到节点之后，需要判断是否为首节点
                # 因为首节点时，还没有Previous这个变量
                if current == self.head:
                    self.head = current.get_next()
                else:
                    previous.set_next(current.get_next())
                break
            else:
                previous = current
                current = current.get_next()

    # 查找指定数据是否存在
    def search(self, item):
        current = self.head
        found = False
        while current is not None:
            if current.get_data() == item:
                found = True
            current = current.get_next()
        return found

    def is_empty(self):
        return self.head is None

    def __len__(self):
        return self.size()

    def size(self):
        count = 0
        current = self.head
        while current is not None:
            count += 1
            current = current.get_next()
        return count

    def show(self):
        current = self.head
        while current is not None:
            print(current.get_data(), end=' ')
            current = current.get_next()
        print('\n')

if __name__ == '__main__':
    s_list = SingleList()
    print(s_list.is_empty())
    s_list.add(5)
    s_list.add(4)
    s_list.add(76)
    s_list.add(23)
    s_list.show()
    s_list.append(47)
    s_list.show()
    s_list.insert(0, 100)
    s_list.show()
    s_list.insert(99, 345)
    s_list.show()
    s_list.insert(3, 222)
    s_list.show()
    s_list.remove(47)
    s_list.show()
    print(s_list.search(76))
    s_list.show()
    print(s_list.is_empty())
    print(s_list.size())
    print(len(s_list))

C:\Users\Sahara\.virtualenvs\test\Scripts\python.exe C:/Users/Sahara/PycharmProjects/test/python_search.py
True

True

False

Process finished with exit code