谈一谈基于python的面向对象编程基础

class Student(object):

 # __init__是一个特殊方法用于在创建对象时进行初始化操作
 # 通过这个方法我们可以为学生对象绑定name和age两个属性
 def __init__(self, name, age):
  self.name = name
  self.age = age

 def study(self, course_name):
  print('%s正在学习%s.' % (self.name, course_name))

 # PEP 8要求标识符的名字用全小写多个单词用下划线连接
 # 但是很多程序员和公司更倾向于使用驼峰命名法(驼峰标识)
 def watch_av(self):
  if self.age < 18:
   print('%s只能观看《熊出没》.' % self.name)
  else:
   print('%s正在观看岛国爱情动作片.' % self.name)

def main():
 # 创建学生对象并指定姓名和年龄
 stu1 = Student('骆昊', 38)
 # 给对象发study消息
 stu1.study('Python程序设计')
 # 给对象发watch_av消息
 stu1.watch_av()
 stu2 = Student('王大锤', 15)
 stu2.study('思想品德')
 stu2.watch_av()


if __name__ == '__main__':
 main()

class Test:

 def __init__(self, foo):
  self.__foo = foo

 def __bar(self):
  print(self.__foo)
  print('__bar')


def main():
 test = Test('hello')
 # AttributeError: 'Test' object has no attribute '__bar'
 test.__bar()
 # AttributeError: 'Test' object has no attribute '__foo'
 print(test.__foo)


if __name__ == "__main__":
 main()

class Test:

 def __init__(self, foo):
  self.__foo = foo

 def __bar(self):
  print(self.__foo)
  print('__bar')


def main():
 test = Test('hello')
 test._Test__bar()
 print(test._Test__foo)


if __name__ == "__main__":
 main()

class Clock(object):
 """数字时钟"""

 def __init__(self, hour=0, minute=0, second=0):
  """初始化方法

  :param hour: 时
  :param minute: 分
  :param second: 秒
  """
  self._hour = hour
  self._minute = minute
  self._second = second

 def run(self):
  """走字"""
  self._second += 1
  if self._second == 60:
   self._second = 0
   self._minute += 1
   if self._minute == 60:
    self._minute = 0
    self._hour += 1
    if self._hour == 24:
     self._hour = 0

 def show(self):
  """显示时间"""
  return '%02d:%02d:%02d' % \
    (self._hour, self._minute, self._second)


def main():
 clock = Clock(23, 59, 58)
 while True:
  print(clock.show())
  sleep(1)
  clock.run()


if __name__ == '__main__':
 main()

from math import sqrt


class Point(object):

 def __init__(self, x=0, y=0):
  """初始化方法
  
  :param x: 横坐标
  :param y: 纵坐标
  """
  self.x = x
  self.y = y

 def move_to(self, x, y):
  """移动到指定位置
  
  :param x: 新的横坐标
  "param y: 新的纵坐标
  """
  self.x = x
  self.y = y

 def move_by(self, dx, dy):
  """移动指定的增量
  
  :param dx: 横坐标的增量
  "param dy: 纵坐标的增量
  """
  self.x += dx
  self.y += dy

 def distance_to(self, other):
  """计算与另一个点的距离
  
  :param other: 另一个点
  """
  dx = self.x - other.x
  dy = self.y - other.y
  return sqrt(dx ** 2 + dy ** 2)

 def __str__(self):
  return '(%s, %s)' % (str(self.x), str(self.y))


def main():
 p1 = Point(3, 5)
 p2 = Point()
 print(p1)
 print(p2)
 p2.move_by(-1, 2)
 print(p2)
 print(p1.distance_to(p2))


if __name__ == '__main__':
 main()