Python面向对象程序设计构造函数和析构函数用法分析

class Person():
  #构造方法
  def __init__(self):
    print("构造函数被执行了")
  #创建对象的过程中构造函数被自动调用
p1 = Person()

class Person():
  #一般情况下,构造方法的参数和成员变量有关,并且在设置的过程中与成员变量同名
  def __init__(self, name, age, height, weight):
    #print(nname, age, height, weight)
    #因为构造方法是创建对象的过程中被调用的
    #所以构造方法的作用一般是用来定义成员变量并且给成员变量赋值
    #定义属性并给属性赋值
    #通过self来进行区分是成员变量还是形参
    self.name = name
    self.age = age
    self.height = height
    self.weight = weight
  def run(self):
    print("run")
  def eat(self, food):
    print("eat "+ food)
'''
构造函数: __init__() 在使用类创建对象的时候自动调用
注意: 如果不显式的写出构造函数,默认会自动添加一个空的构造函数,函数体中什么都不实现
'''
per = Person("hanmeimei", 20, 170, 55)
print(per.name, per.age)
per.run()
per2 = Person("lili", 21, 175, 70)
print(per2.name, per2.age)

class Test():
  def prt(self):
    print(self)
    print(self.__class__)
t = Test()
t.prt()

class Person():
  def run(self):
    print("run")
    print(self.__class__)
    p = self.__class__("tt", 30, 10, 30)
  def eat(self,food):
    print("eat" + food)
  def say(self):
    print("hello, my name is %s, I am %d year old" % (self.name, self.age))
  def play(a):
    print("play", a.name)
  def __init__(self, name, age, height, weight):
    self.name = name
    self.age = age
    self.height = height
    self.weight = weight
# self代表此时正在创建对象,self.属性表示当前对象的属性
per1 = Person("tom", 20, 160, 80)
per1.say()
per2 = Person("henmeimei", 21, 160, 80)
per2.say()
per1.say()
per1.run()

class Person():
  def run(self):
    print("run")
  def eat(self, food):
    print("eat "+food)
  def __init__(self, name, age, height, weight):
    self.name = name
    self.age = age
    self.height = height
    self.weight = weight
   def __del__(self):
    print("析构函数被调用了")
per = Person("hanmeimei", 20, 170, 55)
#释放对象
del per
#注意:对象释放后就不能再进行访问了
#在函数里定义的对象,会在函数结束时自动释放,这样可以用来减少内存空间的浪费
#其实就是作用域的问题
def func():
  per2 = Person("aa", 1, 1, 1)
func()

class Animal(object):
  def __del__(self):
    print('Animal父类的析构函数被调用了')
class Cat(Animal):
  pass
cat = Cat()

class A():
  def __init__(self):
    print("父类A构造函数被调用了")
  def __del__(self):
    print("父类A析构函数被调用了")
class B(A):
  def __init__(self):
    print("子类B构造函数被调用了")
    A.__init__(self)
  def __del__(self):
    print("子类B析构函数被调用了")
class C(A):
  pass
def main():
  b = B()
  del b
  print("*********************")
  c = C()
if __name__ == '__main__':
  main()