静态变量统计实例的数目

#!/usr/bin/env python

class InstanceCount(object):
	count=0

	def __init__(self):
		InstanceCount.count += 1
	
	def __del__(self):
		InstanceCount.count -= 1
	
	def printInstanceCount(self):
		print '='*20
		print "Now instance count=",InstanceCount.count

def main():
	ainstance=InstanceCount()
	
	ainstance.printInstanceCount()
	
	binstance=InstanceCount()
	
	
	ainstance.printInstanceCount()
	
	del ainstance
	
	binstance.printInstanceCount()
	
	del binstance
	


if __name__=="__main__":
	main()	

 注意对于静态变量的改变必须是通过类名的引用才能实现。