python核心编程-标准类派生-不可变类型

#!/usr/bin/env python
# -*- coding: UTF-8 -*-

class RoundFloatA(float):
def __new__(cls, val):
return float.__new__(cls, round(val, 2))

class RoundFloatB(float):
def __new__(cls, val):
return super(RoundFloatB, cls).__new__(cls, round(val, 2))

print RoundFloatA(1.5955)
print RoundFloatB(1.5955)

D:\Python27\test>object05.py
1.6
1.6

D:\Python27\test>