用Python实现堆栈

小编典典

用Python实现堆栈

algorithm

我正在尝试使用数组使用Python实现一个简单的堆栈。我想知道是否有人可以让我知道我的代码出了什么问题。

class myStack:
     def __init__(self):
         self = []

     def isEmpty(self):
         return self == []

     def push(self, item):
         self.append(item)

     def pop(self):
         return self.pop(0)

     def size(self):
         return len(self)

    s = myStack()
    s.push('1')
    s.push('2')
    print(s.pop())
    print s

阅读 220

2020-07-28

共1个答案

小编典典

我更正了以下几个问题。同样，用抽象编程术语来说，“堆栈”通常是一个集合，您可以在其中添加或从顶部删除，但是在实现它的方式上，您是在顶部添加并从底部删除，这使其成为一个队列。
。

class myStack:
     def __init__(self):
         self.container = []  # You don't want to assign [] to self - when you do that, you're just assigning to a new local variable called `self`.  You want your stack to *have* a list, not *be* a list.

     def isEmpty(self):
         return self.size() == 0   # While there's nothing wrong with self.container == [], there is a builtin function for that purpose, so we may as well use it.  And while we're at it, it's often nice to use your own internal functions, so behavior is more consistent.

     def push(self, item):
         self.container.append(item)  # appending to the *container*, not the instance itself.

     def pop(self):
         return self.container.pop()  # pop from the container, this was fixed from the old version which was wrong

     def peek(self):
         if self.isEmpty():
             raise Exception("Stack empty!")
         return self.container[-1]  # View element at top of the stack

     def size(self):
         return len(self.container)  # length of the container

     def show(self):
         return self.container  # display the entire stack as list


s = myStack()
s.push('1')
s.push('2')
print(s.pop())
print(s.show())

2020-07-28