Stack 堆栈存储数据元素 就像一堆盘子在厨房里一个个又一个地存放一样，允许在一端的操作可称为堆栈顶部， 无涯教程只能在堆栈中添加或删除元素。
压入堆栈
class Stack:
</span><span class="kwd">def</span><span class="pln"> __init__</span><span class="pun">(</span><span class="kwd">self</span><span class="pun">):</span><span class="pln">
</span><span class="kwd">self</span><span class="pun">.</span><span class="pln">stack</span><span class="pun">=[]</span><span class="pln">
</span><span class="kwd">def</span><span class="pln"> </span><span class="kwd">add</span><span class="pun">(</span><span class="kwd">self</span><span class="pun">,</span><span class="pln"> dataval</span><span class="pun">):</span><span class="pln">
# 使用列表追加方法添加元素
if dataval not in self.stack:
self.stack.append(dataval)
return True
else:
return False
# 使用 peek 查看栈顶
</span><span class="kwd">def</span><span class="pln"> peek</span><span class="pun">(</span><span class="kwd">self</span><span class="pun">):</span><span class="pln">
</span><span class="kwd">return</span><span class="pln"> </span><span class="kwd">self</span><span class="pun">.</span><span class="pln">stack</span><span class="pun">[-</span><span class="lit">1</span><span class="pun">]</span><span class="pln">
AStack=Stack()
AStack.add("Mon")
AStack.add("Tue")
AStack.peek()
print(AStack.peek())
AStack.add("Wed")
AStack.add("Thu")
print(AStack.peek())
执行以上代码后，将产生以下输出:
Tue Thu
删除数据
众所周知，无涯教程只能从堆栈中删除过多的数据元素，以下程序中的remove函数返回最顶部元素。
class Stack:
</span><span class="kwd">def</span><span class="pln"> __init__</span><span class="pun">(</span><span class="kwd">self</span><span class="pun">):</span><span class="pln">
</span><span class="kwd">self</span><span class="pun">.</span><span class="pln">stack</span><span class="pun">=[]</span><span class="pln">
</span><span class="kwd">def</span><span class="pln"> </span><span class="kwd">add</span><span class="pun">(</span><span class="kwd">self</span><span class="pun">,</span><span class="pln"> dataval</span><span class="pun">):</span><span class="pln">
# 使用列表追加方法添加元素
if dataval not in self.stack:
self.stack.append(dataval)
return True
else:
return False
# 使用 peek 查看栈顶
</span><span class="kwd">def</span><span class="pln"> peek</span><span class="pun">(</span><span class="kwd">self</span><span class="pun">):</span><span class="pln">
</span><span class="kwd">return</span><span class="pln"> </span><span class="kwd">self</span><span class="pun">.</span><span class="pln">stack</span><span class="pun">[-</span><span class="lit">1</span><span class="pun">]</span><span class="pln">
AStack=Stack()
AStack.add("Mon")
AStack.add("Tue")
AStack.peek()
print(AStack.peek())
AStack.add("Wed")
AStack.add("Thu")
print(AStack.peek())
Thu Wed
