使用 List 物件建立 Stack 類

使用 list 物件，你可以使用輔助方法建立一個功能齊全的通用堆疊，例如窺視和檢查堆疊是否為空。檢視官方 python 文件，在這裡使用 list 作為 Stack 。

#define a stack class
class Stack:
    def __init__(self):
        self.items = []
    
    #method to check the stack is empty or not
    def isEmpty(self):
        return self.items == []
    
    #method for pushing an item 
    def push(self, item):
        self.items.append(item)

    #method for popping an item 
    def pop(self):
        return self.items.pop()
    
    #check what item is on top of the stack without removing it
    def peek(self):
        return self.items[-1]

    #method to get the size
    def size(self):
        return len(self.items)

    #to view the entire stack
    def fullStack(self):
        return self.items

一個示例執行：

stack = Stack()
print('Current stack:', stack.fullStack())
print('Stack empty?:', stack.isEmpty())
print('Pushing integer 1')
stack.push(1)
print('Pushing string "Told you, I am generic stack!"')
stack.push('Told you, I am generic stack!')
print('Pushing integer 3')
stack.push(3)
print('Current stack:', stack.fullStack())
print('Popped item:', stack.pop())
print('Current stack:', stack.fullStack())
print('Stack empty?:', stack.isEmpty())

輸出：

Current stack: []
Stack empty?: True
Pushing integer 1
Pushing string "Told you, I am generic stack!"
Pushing integer 3
Current stack: [1, 'Told you, I am generic stack!', 3]
Popped item: 3
Current stack: [1, 'Told you, I am generic stack!']
Stack empty?: False