魔术方法-析构函数
析构函数,str和repr方法
class People(object):
def __init__(self, name, age):
self.name = name
self.age = age
print("创建对象成功.......")
def __del__(self):
print("删除对象成功.......")
def __str__(self):
return 'People(%s, %d)' %(self.name, self.age)
def __repr__(self):
return "People(%s)" %(self.name)
def __hello(self):
print("hello")
def world(self):
self.__hello()
if __name__ == '__main__':
p1 = People('fentiao', 12)
print(p1)
print(p1.__str__())
p1.world()
print(str(p1))
print(repr(p1))
del p1
图书管理系统
class Book(object):
def __init__(self, name, author, state, bookIndex):
self.name = name
self.author = author
self.state = state
self.bookIndex = bookIndex
def __str__(self):
return 'Book(%s, %d)' %(self.name, self.state)
class BookManage(object):
books = []
def start(self):
"""图书管理系统初始化数据"""
self.books.append(Book('python', 'Guido', 1, 'IN23445'))
self.books.append(Book('java', 'Guido1', 1, 'IN23445'))
self.books.append(Book('C++', 'Guido2', 1, 'IN23445'))
print("初始化数据成功!")
def Menu(self):
"""图书管理菜单栏"""
while True:
print("""
图书管理操作
1). 添加书籍
2). 删除数据
3). 查询书籍
4). 退出
""")
choice = input("请输入你的选择:")
if choice == '1':
self.addBook()
elif choice == '2':
self.delBook()
elif choice == '3':
self.borrowBook()
elif choice == '4':
exit()
else:
print("请输入正确的选择!")
def addBook(self):
print("添加书籍".center(0, '*'))
name = input("书籍名称:")
bObj = self.isBookExist(name)
if bObj:
print("书籍%s已经存在" %(bObj.name))
else:
self.books.append(Book(name,input("作者:"), 1, input("存放位置:")))
print("书籍%s添加成功" %(name))
def delBook(self):
print("删除书籍".center(50,'*'))
for i in self.books:
print(i)
name = input("删除书籍名称:")
a = self.isBookExist(name)
if a:
self.books.remove(a)
print("删除%s成功" %(a))
else:
print("书籍不存在")
def borrowBook(self):
print("查询书籍".center(50,'*'))
for i in self.books:
print(i)
name = input("查询书籍名称:")
b = self.isBookExist(name)
for book in self.books:
if book == b:
print(book)
break
else:
print("%s不存在" %(b))
break
def isBookExist(self, name):
"""检测书籍是否存在"""
for book in self.books:
if book.name == name:
return book
else:
return False
if __name__ == "__main__":
bManger = BookManage()
bManger.start()
bManger.Menu()
formats = {
'ymd':"{d.year}-{d.month}-{d.day}",
'mdy':"{d.month}/{d.day}/{d.year}",
}
class Date(object):
def __init__(self, year, month, day):
self.year = year
self.month = month
self.day = day
def __format__(self, format_spec=None):
if not format_spec:
format_spec = 'ymd'
fmt = formats[format_spec]
return fmt.format(d=self)
d = Date(2019, 8, 25)
print(format(d))
print(format(d, 'mdy'))
print(d.__format__('ymd'))
print(format(d, 'ymd'))
print("name:%s, age:%d, scores:%s" % ('westos', 10, dict(a=1, b=2)))
print("name:%s, age:%d, scores:%s" % ('westos', 10, (1, 2)))
print("name:%s, age:%d, name:%s" % ('westos', 10, 'westos'))
print("name:{0}, age:{1}, scores:{2}".format('westos', 10, [100, 100, 100]))
print("name:{0}, age:{1}, scores:{0}".format('westos', 10))
print("name:{0}, id:{1:.3f}, scores:{0}".format('westos', 19.2332435))
d = {'max': 100, 'min': 10}
print("MAX: {max}, MIN:{min}".format(max=100, min=10))
print("MAX: {max}, MIN:{min}".format(**d))
point = (3,4)
print("x:{0[0]}, y:{0[1]}".format(point))
class Book(object):
def __init__(self, name, author, state, bookIndex):
self.name = name
self.author = author
self.state = state
self.bookIndex = bookIndex
def __str__(self):
return 'Book(%s, %d)' %(self.name, self.state)
b = Book('python', 'guido', 1, 'IND444')
print("name:{b.name}, state:{b.state}, author:{b.state}".format(b=b))
print("name:{0.name}, state:{0.state}, author:{0.state}".format(b))
类内部装饰器 property
没有使用装饰器property的情况下
class Book(object):
def __init__(self, name, author, state, bookIndex):
self.name = name
self.author = author
self.__state = state
self.bookIndex = bookIndex
def get_state(self):
if self.__state == 0:
return '已借出'
elif self.__state == 1:
return '未借出'
else:
return "状态异常"
def set_state(self, value):
if value in (0,1):
self.__state = value
def del_state(self):
print("is deleteing......")
def __str__(self):
return 'Book(%s, %d)' %(self.name, self.__state)
state = property(fget=get_state, fset=set_state, fdel=del_state)
b = Book('python', 'guido', 1, 'chddf')
print(b.state)
b.state = 0
print(b.state)
del b.state
使用装饰器property时
class Book(object):
def __init__(self, name, author, state, bookIndex):
self.name = name
self.author = author
self.__state = state
self.bookIndex = bookIndex
@property
def state(self):
if self.__state == 0:
return '已借出'
elif self.__state == 1:
return '未借出'
else:
return "状态异常"
@state.setter
def state(self, value):
if value in (0,1):
self.__state = value
@state.deleter
def state(self):
print("is deleteing......")
def __str__(self):
return 'Book(%s, %d)' %(self.name, self.__state)
b = Book('python', 'guido', 1, 'chddf')
print(b.state)
b.state = 10
print(b.state)
print(b.state)
b.state = 0
print(b.state)
del b.state
类的索引,切片,成员操作符
索引
li = [1,2,3,4,5,6]
__getitem__: li[0] === __getslice__
__setitem__: li[0] = 10 == __setslice__
__delitem__: del li[0] == __delslice__]
class Student(object):
def __init__(self, name, scores):
self.name = name
self.scores = scores
def __getitem__(self, index):
return self.scores[index]
def __setitem__(self, index, value):
self.scores[index] = value
def __delitem__(self, index):
del self.scores[index]
def hello(self):
return "hello"
s = Student('westos', [101, 100, 100])
print(s[0])
print(s[1])
print(s[2])
s[0] = 200
print(s[0])
print(s.scores)
del s[0]
print(s.scores)
字典的索引
class Student(object):
def __init__(self, name, scores):
self.name = name
self.scores = scores
def __getitem__(self, key):
return self.__dict__[key]
def __setitem__(self, key, value):
self.__dict__[key] = value
def __delitem__(self, key):
del self.__dict__[key]
def hello(self):
return "hello"
s = Student('westos', [101, 100, 100])
print(s['name'])
print(s['scores'])
s['name'] = 'westo1'
print(s['name'])
del s['name']
print(s['name'])
切片
class Student(object):
def __init__(self, name, scores):
self.name = name
self.scores = scores
def __getitem__(self, key):
return self.scores[key]
def __setitem__(self, key, value):
self.scores[key] = value
def __delitem__(self, key):
del self.scores[key]
s = Student('westos', [101, 90, 101])
print(s[1:3])
s[1:3] = [0,0]
print(s[:])
del s[:-1]
print(s[:])
print(s[0])
重复,连接,成员操作符
class Student(object):
def __init__(self, name, scores):
self.name = name
self.scores = scores
self.power = 100
def __add__(self, other):
self.power = self.power + other.power
return self
def __mul__(self, other):
return self.power * other
def __contains__(self, item):
return item in self.scores
def __iter__(self):
"""
iter([1,2,3,4,5])
<list_iterator object at 0x7f6e1f51ffd0>
iter({1,2,3,4,5})
<set_iterator object at 0x7f6e1f567318>
"""
return iter(self.scores)
def __repr__(self):
return "Student:%s,%s" %(self.name, self.power)
print("hello " + "world")
print([1,2,3] + [3,4,5])
s1 = Student('westos1', [101,100,100])
s2 = Student('westos2', [100,100,100])
s3 = Student('westos3', [100,100,100])
print(s1 + s2 + s3)
s1 += s2
print(s1)
a = 3
print(a*3)
s = 'a'
print(s*3)
li = [1,2,3]
print(li*3)
print(s1*3)
print(s1.scores)
print(200 in s1)
print(100 in s1)
print(200 not in s1)
print(100 not in s1)
for i in s1:
print(i)
print(isinstance(s1, Iterable)
call方法
from django.core.paginator import Page
class Student(object):
def __init__(self, name, scores, power):
self.name = name
self.scores = scores
self.power = power
def __call__(self, *args, **kwargs):
return "对象被调用......"
def __new__(cls, *args, **kwargs):
if not hasattr(cls, 'obj'):
cls.obj = object.__new__(cls)
return cls.obj
s1 = Student('westos1', [101,100,100], 100)
s2 = Student('westos1', [101,100,100], 100)
print(s1)
print(s2)