顺序表
python中的list和tuple就采用了顺序表的实现技术
tuple是不变的表，因此不支持改变其内部状态的任何操作
list是一种元素个数可变的线性表，可以加入和删除元素，在各种操作中维持已有元素的顺序
list对象无法设置容量的操作
if __name__ == '__main__':
lt = list([1, 3, 2])
print(len(lt)) # 3
print(lt) # [1, 3, 2]
# 元素顺序倒置
lt.reverse()
print(lt) # [2, 3, 1]
# 排序
lt.sort()
print(lt) # [1, 2, 3]
# 清除表中所有元素
lt.clear()
print(len(lt)) # 0
单链表：
单链表头部添加元素：
class LNode:
"""表节点"""
# next_防止与标准函数next重名
def __init__(self, elem, next_=None):
self.elem = elem
self.next = next_
class LinkedListUnderflow(ValueError):
pass
class LList:
"""单链表"""
def __init__(self):
self._head = None
def is_empty(self):
"""链表是否为空"""
return self._head is None
def __len__(self):
"""链表长度"""
count = 0
p = self._head
while p:
count += 1
p = p.next
return count
def prepend(self, elem):
"""表头插入数据"""
# node = LNode(elem)
# node.next = self._head
# self._head = node
# 合并为一句
self._head = LNode(elem, self._head)
def pop(self):
"""删除头一个元素"""
if self._head is None: # 无结点，抛出异常
raise LinkedListUnderflow("in pop")
e = self._head.elem
self._head = self._head.next
return e
def append(self, elem):
"""尾部添加元素"""
if self._head is None:
self._head = LNode(elem)
return
p = self._head
while p.next is not None:
p = p.next
p.next = LNode(elem)
def printall(self):
p = self._head
while p:
print(p.elem, end='')
if p.next:
print(', ', end='')
p = p.next
print('')
def for_each(self, proc):
"""遍历函数，proc的参数应该是可以作用于表元素的操作函数，如：print"""
p = self._head
while p:
proc(p.elem)
p = p.next
def elements(self):
"""迭代器"""
p = self._head
while p:
yield p.elem
p = p.next
def find(self, pred):
"""返回符合条件的第一个"""
p = self._head
while p is not None:
if pred(p.elem):
return p.elem
p = p.next
def filter(self, pred):
"""筛选生成器"""
p = self._head
while p is not None:
if pred(p.elem):
yield p.elem
p = p.next
if __name__ == '__main__':
llist1 = LNode(1)
p = llist1
for i in range(2, 11):
p.next = LNode(i)
p = p.next
p = llist1
# 可简写 while p:
while p is not None:
print(p.elem)
p = p.next
mlist1 = LList()
for i in range(3):
mlist1.prepend(i)
for i in range(4, 7):
mlist1.append(i)
mlist1.printall() # 2, 1, 0, 4, 5, 6
mlist1.for_each(print)
print("-------")
for x in mlist1.elements():
print(x, end=' ') # 2 1 0 4 5 6
print("-------")
print(mlist1.find(lambda z: z > 3)) # 4
print("-------")
for x in mlist1.filter(lambda z: z > 3):
print(x, end=' ') # 4 5 6
print("-------")
print(len(mlist1)) # 6
带有尾节点引用的单链表：
头部添加元素:
class LList2(LList):
"""带有尾节点引用的单链表"""
def __init__(self):
# 相当于LList.__init__()
super(LList2, self).__init__()
self._rear = None
def prepend(self, elem):
"""表头插入数据"""
if self._head is None:
self._head = LNode(elem, self._head)
self._rear = self._head
else:
self._head = LNode(elem, self._head)
def append(self, elem):
"""尾部添加元素"""
if self._head is None:
self._head = LNode(elem, self._head)
self._rear = self._head
else:
self._rear.next = LNode(elem)
self._rear = self._rear.next
def pop_last(self):
"""弹出末尾元素"""
if self._head is None:
raise LinkedListUnderflow("in pop_last")
p = self._head
# 只有一个元素
# 表判断空用_head的值，所有删除最后一个结点使表变空时，不需要给_rear赋值None
if p.next is None:
e = p.elem
self._head = None
return e
while p.next.next:
p = p.next
e = p.next.elem
p.next = None
self._rear = p
return e
if __name__ == '__main__':
mlist1 = LList2()
mlist1.prepend(1)
mlist1.prepend(2)
for i in range(3, 5):
mlist1.append(i)
for i in mlist1.elements():
print(i, end=' ') # 2 1 3 4
print("---------")
print(mlist1.pop_last()) # 4