#1.創(chuàng)建Person類
#2.繼承object
#3.擁有屬性eat
class Person(object):
? ? def eat(self,food="rice"):
? ? ? ? print("eat %s"%food)
p = Person()
p.eat(food="fruits")

def eat(self,food="rice"):
? ? print("eat %s"%food)
People = type("People",(object,),{"eat":eat})
#People = type("People",(object,),dict(eat=eat))
p = People()
p.eat()

#方式1，使用lambda匿名函數(shù)
class LanguageMetaClass(type):
? ? def __new__(cls, name, bases, attrs):
? ? ? ? attrs['speak'] = lambda self:print(self.language)
? ? ? ? return type.__new__(cls,name,bases,attrs)
#方式2，使用預定義的函數(shù)
def speak(self):
? ? print("speak %s"%self.language)
#創(chuàng)建元類LanguageMetaClass
class LanguageMetaClass(type):
? ? def __new__(cls, name, bases, attrs):
? ? ? ? attrs['speak'] = speak
? ? ? ? #return type.__new__(cls,name,bases,attrs)
? ? ? ? return super(LanguageMetaClass,cls).__new__(cls.name,bases,attrs)
#使用創(chuàng)建好的元類創(chuàng)建類(python2.x與3.x方式不一致)
#python2.x
#默認新式類由type()構造，當在類中定義了__metaclass__則由其構建，__metaclass__查找順序：
#1.查找自身的__metaclass__屬性
#2.如果有父類，查找父類的__metaclass__（通過父類.__class__屬性獲?。?
#3.如果沒有父類，查找模塊中的__metaclass__
class People(object):
? ? __metaclass__ = LanguageMetaClass ??
? ? def __init__(self,language="chinese"):
? ? ? ? self.language = language
#python3.x
#默認新式類由type()構造，可以通過指定metaclass關鍵字參數(shù)后，則由metaclass構造
class People(object,metaclass=LanguageMetaClass): ??
? ? def __init__(self,language="chinese"):
? ? ? ? self.language = language
p1 = People(language="English")
p1.speak() ? ?#speak English
p2 = People()
p2.speak() ? ?#speak chinese

#創(chuàng)建元類AddMetaClass
class AddMetaClass(type):
? ? def __new__(cls,name,bases,attrs):
? ? ? ? attrs['add'] = lambda self,value:self.append(value)
? ? ? ? return type.__new__(cls,name,bases,attrs)
#python2.x
class MyList(list): ? ?#MyLIST在list的基礎上多了個add方法
? ? __metaclass__ = AddMetaClass
? ? pass
? ??
#python3.x
class MyList(list,metaclass=AddMetaClass): ? ?#MyLIST在list的基礎上多了個add方法
? ? pass
list1 =MyList()
list1.add(1)
print(list1) ? ?#[1]
list1.add(2)
print(list1) ? ?#[1,2]

print(type(1))
print(type('abc'))
print(type([]))

print(isinstance((),tuple))
print(isinstance('abc',str))
print(isinstance([],list))

type("Foo", (object,), {"a":1})