标签：python sleep charset die list ini 模仿 str while
类有两种属性：数据属性和函数属性
1、类的数据属性是所有对象共享的
class LuffyStudent:
school=‘luffycity‘
def learn(self):
print(‘is learning‘)
def eat(self):
print(‘is sleeping‘)
#后产生对象
stu1=LuffyStudent()
stu2=LuffyStudent()
stu3=LuffyStudent()
print(id(stu1.school))
print(id(stu2.school))
print(id(stu3.school))
# 43496496
# 43496496
# 43496496
2、类的函数数据是绑定给对象用的，称为绑定到对象的方法
#后产生对象 stu1=LuffyStudent() stu2=LuffyStudent() stu3=LuffyStudent() #类的函数属性是绑定给对象使用的,obj.method称为绑定方法,内存地址都不一样 print(stu1.learn()) print(stu2.learn()) print(stu3.learn()) # <bound method LuffyStudent.learn of <__main__.LuffyStudent object at 0x00000000127085C0>> # <bound method LuffyStudent.learn of <__main__.LuffyStudent object at 0x0000000012708518>> # <bound method LuffyStudent.learn of <__main__.LuffyStudent object at 0x0000000012708630>> #ps:id是python的实现机制,并不能真实反映内存地址,如果有内存地址,还是以内存地址为准
在obj.name会先从obj自己的名称空间里找name，找不到则去类中找，类也找不到就找父类...最后都找不到就抛出异常
定义类并实例化出三个对象
class LuffyStudent:
school=‘luffy‘
def __init__(self,name,age):
self.name = name
self.age = age
def eat(self):
print(‘%s is eating‘ %self.name)
def sleep(self):
print(‘%s is sleeping‘ %self.name)
def __del__(self):
print("running del method, this person must be died.")
# 后产生对象
stu1=LuffyStudent(‘alex‘,18)
stu2=LuffyStudent(‘li‘,28)
stu3=LuffyStudent(‘hy‘,38)
stu1.eat()
stu2.eat()
stu3.eat()
# alex is eating
# li is eating
# hy is eating
强调：绑定到对象的方法的特殊之处在于，绑定给谁就由谁来调用，谁来调用，就会将‘谁’本身当做第一个参数传给方法，即自动传值（方法__init__也是一样的道理）
stu1.eat() # 等同于LuffyStudent.eat(stu1) stu2.eat() # 等同于LuffyStudent.eat(stu1) stu3.eat() # 等同于LuffyStudent.eat(stu1)
注意：绑定到对象的方法的这种自动传值的特征，决定了在类中定义的函数都要默认写一个参数self，self可以是任意名字，但是约定俗成地写出self。
python中一切皆为对象，且python3中类与类型是一个概念，类型就是类
#类型dict就是类dict >>> list <class ‘list‘> #实例化的到3个对象l1,l2,l3 >>> l1=list() >>> l2=list() >>> l3=list() #三个对象都有绑定方法append,是相同的功能,但内存地址不同 >>> l1.append <built-in method append of list object at 0x10b482b48> >>> l2.append <built-in method append of list object at 0x10b482b88> >>> l3.append <built-in method append of list object at 0x10b482bc8> #操作绑定方法l1.append(3),就是在往l1添加3,绝对不会将3添加到l2或l3 >>> l1.append(3) >>> l1 [3] >>> l2 [] >>> l3 [] #调用类list.append(l3,111)等同于l3.append(111) >>> list.append(l3,111) #l3.append(111) >>> l3 [111]
class MySQLHandler:
def __init__(self,host,port,db,charset=‘utf8‘):
self.host=host
self.port=port
self.db=db
self.charset=charset
self.conn=self.connect(self.host,self.port,self.db,self.charset)
def exc1(self,sql):
return self.conn.execute(sql)
def exc2(self,sql):
return self.conn.call_proc(sql)
def _connect(self,host,port,db,charset):
print(‘connect %s,%s,%s,%s‘ %(host,port,db,charset))
obj=MySQLHandler(‘127.0.0.1‘,3306,‘db1‘)
obj.exc1(‘select * from tb1;‘)
obj.exc2(‘mycall‘)
练习1：编写一个学生类，产生一堆学生对象
要求：
class Student(object):
count = 0
def __init__(self,name):
self.name = name
Student.count+=1
def learn(self):
print(‘%s is learning‘%self.name)
s1 = Student(‘x1‘)
print(s1.count) # 1
s2 = Student(‘x2‘)
print(s2.count) # 2
s3 = Student(‘x3‘)
print(s3.count) # 3
练习2：模仿王者荣耀定义两个英雄类
要求：
class HeroA:
camp = ‘A‘
def __init__(self,name,life_vale,aggresivity):
self.name = name
self.life_value = life_vale
self.aggresivity = aggresivity
def attack(self,enemy):
if enemy.life_value == 0:
print(‘%s is dead‘ %enemy.name)
enemy.life_value -= self.aggresivity
class HeroB:
camp =‘B‘
def __init__(self,name,life_vale,aggresivity):
self.name = name
self.life_value = life_vale
self.aggresivity = aggresivity
def attack(self,enemy):
if enemy.life_value == 0:
print(‘%s is dead‘ % enemy.name)
enemy.life_value -= self.aggresivity
a = HeroA(‘a1‘,160,50)
b = HeroB(‘b1‘,150,40)
while b.life_value > 0:
a.attack(b)
print(‘b life‘, b.life_value)
b.attack(a)
print(‘a life‘, a.life_value)
a.attack(b)
#结果
b life 100
a life 120
b life 50
a life 80
b life 0
a life 40
b1 is dead
标签：python sleep charset die list ini 模仿 str while
原文地址：https://www.cnblogs.com/xiao-apple36/p/9127751.html
