1.类属性
#!/usr/bin/python
# Filename: objvar.py
class Person:
'''Represents a person.'''
population = 0
def __init__(self, name):
'''Initializes the person's data.'''
self.name = name
print('(Initializing %s)',self.name)
# When this person is created, he/she
# adds to the population
Person.population += 1
def __del__(self):
'''I am dying.'''
print('%s says bye.',self.name)
Person.population -= 1
if Person.population == 0:
print('I am the last one.')
else:
print('There are still %d people left.', Person.population)
def sayHi(self):
'''Greeting by the person.
Really, that's all it does.'''
print('Hi, my name is %s.',self.name)
def howMany(self):
'''Prints the current population.'''
if Person.population == 1:
print('I am the only person here.')
else:
print('We have %d persons here.', Person.population)
swaroop = Person('Swaroop')
swaroop.sayHi()
swaroop.howMany()
kalam = Person('Abdul Kalam')
kalam.sayHi()
kalam.howMany()
swaroop.sayHi()
swaroop.howMany()
输出
$ python objvar.py
(Initializing Swaroop)
Hi, my name is Swaroop.
I am the only person here.
(Initializing Abdul Kalam)
Hi, my name is Abdul Kalam.
We have 2 persons here.
Hi, my name is Swaroop.
We have 2 persons here.
Abdul Kalam says bye.
There are still 1 people left.
Swaroop says bye.
I am the last one.
还有一个特殊的方法del，它在对象消逝的时候被调用
2.继承
#!/usr/bin/python
# Filename: inherit.py
class SchoolMember:
'''Represents any school member.'''
def __init__(self, name, age):
self.name = name
self.age = age
print '(Initialized SchoolMember: %s)' % self.name
def tell(self):
'''Tell my details.'''
print 'Name:"%s" Age:"%s"' % (self.name, self.age),
class Teacher(SchoolMember):
'''Represents a teacher.'''
def __init__(self, name, age, salary):
SchoolMember.__init__(self, name, age)
self.salary = salary
print '(Initialized Teacher: %s)' % self.name
def tell(self):
SchoolMember.tell(self)
print 'Salary: "%d"' % self.salary
class Student(SchoolMember):
'''Represents a student.'''
def __init__(self, name, age, marks):
SchoolMember.__init__(self, name, age)
self.marks = marks
print '(Initialized Student: %s)' % self.name
def tell(self):
SchoolMember.tell(self)
print 'Marks: "%d"' % self.marks
t = Teacher('Mrs. Shrividya', 40, 30000)
s = Student('Swaroop', 22, 75)
print # prints a blank line
members = [t, s]
for member in members:
member.tell() # works for both Teachers and Students
结果
$ python inherit.py
(Initialized SchoolMember: Mrs. Shrividya)
(Initialized Teacher: Mrs. Shrividya)
(Initialized SchoolMember: Swaroop)
(Initialized Student: Swaroop)
Name:"Mrs. Shrividya" Age:"40" Salary: "30000"
Name:"Swaroop" Age:"22" Marks: "75"
