终于学到PYTHON的类啦~~

#!/usr/bin/python
# Filename:objvar.py

class Robot:
'''Represents a robot,with a name.'''

population = 0

def __init__(self,name):
'''Iinitializes the data.'''
self.name = name
print('(Initialize {0})'.format(self.name))

Robot.population += 1

def __del__(self):
'''I am dying'''
print('{0} is being destroyed!'.format(self.name))

Robot.population -= 1

if Robot.population == 0:
print('{0} was the last one.'.format(self.name))
else:
print('There are still {0:d} robots working.'.format(Robot.population))

def sayHi(self):
'''Greeting by the robot.

Yeah,they can do that.'''
print('Greetings, my master call me{0}.'.format(self.name))

def howMany():
'''Print the current population.'''
print('We have {0:d} robots.'.format(Robot.population))
howMany = staticmethod(howMany)

droid1 = Robot('R2-D2')
droid1.sayHi()
Robot.howMany()

droid2 = Robot('C-3P0')
droid2.sayHi()
Robot.howMany()

print('\nRobots can do some work here.\n')

print("Robots have finished their work. So let's destroy them.")

del droid1
del droid2

Robot.howMany()