push(a) # 壓入，將a壓入的棧中
pop(） # 彈出，將棧的最后一個(gè)元素彈出

class Stack(object):
  """使用數(shù)組實(shí)現(xiàn)一個(gè)棧"""
  def __init__(self):
    self.data = []
  def push(self, num):
    """壓棧操作"""
    self.data.append(num)
  def pop(self):
    """返回從棧中彈出的元素, 當(dāng)棧為空的時(shí)候, 拋出IndexError"""
    return self.data.pop()
  def peek(self):
    """查看當(dāng)前棧頂?shù)脑? 當(dāng)棧為空的時(shí)候, 拋出IndexError"""
    return self.data[-1]
  def __len__(self):
    """返回棧的長(zhǎng)度, 調(diào)用len(obj)時(shí)會(huì)自動(dòng)調(diào)用obj對(duì)象的__len__方法"""
    return len(self.data)
  def isEmpty(self):
    """判斷棧是否為空"""
    return True if len(self.data)==0 else False
  def clear(self):
    """清空棧"""
    self.data = []
  def __repr__(self):
    """當(dāng)前對(duì)象的表現(xiàn)形式, 在終點(diǎn)直接鍵入對(duì)象時(shí)會(huì)調(diào)用"""
    return 'Stack_' + str(self.data)
  def __str__(self):
    """當(dāng)前對(duì)象的字符串表示, 使用print(obj)時(shí)會(huì)調(diào)用"""
    return 'Stack_' + str(self.data)

(...)...(...)
(...)...(...
)...((...)
def isBalance(text):
  """棧的應(yīng)用,檢查括號(hào)是否平衡"""
  result_stack = Stack()
  for i in text:
    if i in ['{', '[', '(']:
      result_stack.push(i)
    elif i in ['}', ']', ')']:
      # 遇到結(jié)束括號(hào)的情況
      if result_stack.isEmpty():
        # 如果當(dāng)前棧為空, 不匹配,返回False
        return False
      chFromStack = result_stack.pop()
      if not ((chFromStack == '{' and i == '}' )
          or (chFromStack == '[' and i == ']')
          or (chFromStack == '(' and i == ')')):
        # 如果不滿足匹配條件, 則返回False
        return False
  # 遍歷結(jié)束后, 如果結(jié)果棧為空, 則代表括號(hào)匹配, 棧不為空, 括號(hào)不匹配
  return result_stack.isEmpty()

stack = []
stack.append(<item>)

stack.pop(-1) #stack.pop()也可 

stack = []
stack.append(<item>)

stack.pop(0)