You can read more about both from here. But here's a simple example from the same book that tries to explain the differnce solving what essentialy is the same problem. As you can see, the implementation using properties is much simpler.
There are several ways that we can tap into Python's internal mechanisms for getting and setting attribute values. The most accessible technique is to use the property function to define get, set and delete methods associated with an attribute name. The property function builds descriptors for you. A slightly less accessible, but more extensible and reusable technique is to define descriptor classes yourself. This allows you considerable flexibility. You do this by creating a class which defines get, set and delete methods, and you associate your descriptor class with an attribute name.
The property function gives us a handy way to implement a simple descriptor without defining a separate class. Rather than create a complete class definition,
we can write getter and setter method functions, and then bind these functions to an attribute name.
Descriptor example:
class Celsius( object ):
def __init__( self, value=0.0 ):
self.value= float(value)
def __get__( self, instance, owner ):
return self.value
def __set__( self, instance, value ):
self.value= float(value)
class Farenheit( object ):
def __get__( self, instance, owner ):
return instance.celsius * 9 / 5 + 32
def __set__( self, instance, value ):
instance.celsius= (float(value)-32) * 5 / 9
class Temperature( object ):
celsius= Celsius()
farenheit= Farenheit()
>>>
oven= Temperature()
>>>
oven.farenheit= 450
>>>
oven.celsius
232.22222222222223
>>>
oven.celsius= 175
>>>
oven.farenheit
347.0
Property example:
class Temperature( object ):
def fget( self ):
return self.celsius * 9 / 5 + 32
def fset( self, value ):
self.celsius= (float(value)-32) * 5 / 9
farenheit= property( fget, fset )
def cset( self, value ):
self.cTemp= float(value)
def cget( self ):
return self.cTemp
celsius= property( cget, cset, doc="Celsius temperature" )
>>>
oven= Temperature()
>>>
oven.farenheit= 450
>>>
oven.celsius
232.22222222222223
>>>
oven.celsius= 175
>>>
oven.farenheit
347.0
