浅谈Python反射 & 单例模式

class Info:
 
   def __init__(self,name,age,gender):
     self.name = name
     self.age = age
     self.gender = gender
   def show(self):
     return '%s - %s' %(self.name,self.age)
 
obj = Info('alex','20','男')
 
b = 'name'
print(obj.__dict__[b])
print(obj.__dict__['name'])
 
#getattr()
inp = input('请输入想要获取的内容：')
v = getattr(obj,inp)
print(v)
 
func = getattr(obj,'show')
v = func()
print(v)
 
#hasattr()
print(hasattr(obj,'name'))
 
#setattr()
setattr(obj,'k1','v1')
 
#delattr(obj,'gender')
obj.gender # 此时报错，Info类中的gender对象已被删除

class Info(object):
  staticField = "Hello World!"
 
  def __init__(self):
    self.name = 'mike'
 
  def func(self):
    return 'func'
 
  @staticmethod
  def bar():
    return 'bar'
 
print(getattr(Info, 'staticField'))
print(getattr(Info, 'func'))  # 返回函数的内存地址
print(getattr(Info, 'bar'))  # 返回函数的内存地址
 

class Info:
  __v = None
 
  @classmethod
  def get_instance(cls):
    if cls.__v:
      return cls.__v
    else:
      cls.__v = Info()
      return cls.__v
 
obj1 = Info.get_instance()
print(obj1)
obj2 = Info.get_instance()
print(obj2)