python - property() returns different values -

i trying fill gap in understanding of pythons property(). below code have come with, understand property():

class temperature:     def __init__(self, temp = 10):         self.set_temp(temp)      def to_farenheit(self):         return (self._temp * 1.8) + 32      def get_temp(self):         print "getting temperature value"         return self._temp      def set_temp(self, temp):         print "setting temperature value"          if temp < -237:             raise valueerror("this shud above -273")         else:             self._temp = temp      temps = property(get_temp, set_temp) 

i execute above class , following:

>>> t = temperature() setting temperature value  >>> t.temps getting temperature value 10  >>> t.temps = 13  >>> t.temps 13 >>> t.get_temp() getting temperature value 10 >>>  

as can see above, when try set temp value assigning t.temps = 13 set_temp() function not getting called expecting called because of property() functionality. ending 2 different values variable temp

what missing?

it's because use python 2 , forgot subclass object. in case property doesn't work because it's old-style class.

better subclass object:

class temperature(object):     ... 

or better: use python 3. python 3 doesn't have old-style classes anymore , can omit (object) part because it's implicit.

however shouldn't define get_temp or set_temp functions when use decorator syntax. , shouldn't call them directly.

this more pythonic:

class temperature(object):     def __init__(self, temp = 10):         self.temps = temp      def to_farenheit(self):         return (self._temp * 1.8) + 32      @property     def temps(self):         print("getting temperature value")         return self._temp      @temps.setter     def temps(self, temp):         print("setting temperature value")         if temp < -237:             raise valueerror("this shud above -273")         else:             self._temp = temp 

that example work on python 2 and python 3.