Python Forum

This is a little tricky one. Needs more attention since it is a minute thing. There are two classes in the given code. 'celsius' attribute of temperature is handled by 'Celsius' descriptor. Requirement is to have temperature maintained in both fahrenheit and celsius. When executed the code below, as per my understanding, the output should be

32 0.0
32.0 0.0

but the one we get is

32 0.0
32 0.0

Can anyone help me understand why the fahrenheit value in the second line is still an 'int' eventhough it is converted into 'float' in the __set__ method in the descriptor class?

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#!/bin/python3

import sys
import os 

class Celsius():
    def __get__(self, instance, owner):
        return float(self.__celsius)
    def __set__(self, instance, value):
        self.__celsius = value
        self.__fahrenheit = float(value * 9/5 + 32)

class Temperature():
    celsius=Celsius()
    def __init__(self,fahrenheit):
        self.fahrenheit=fahrenheit
        self.celsius=(fahrenheit-32)*(5/9)

t1 = Temperature(32)[size=medium][/size]
print(t1.fahrenheit, t1.celsius)
t1.celsius=0
print(t1.fahrenheit, t1.celsius)

This should point out the problem. You are not seeing Celsius.__Fahrenheit

t1.celsius=10
print(t1.fahrenheit, t1.celsius)

Output:
32 10.0

class Temperature():
    def __init__(self, fahrenheit):
        self.__fahrenheit = fahrenheit

    @property
    def celsius(self):
        return (self.__fahrenheit - 32) * 5/9

    @celsius.setter
    def celsius(self, value):
        self.__fahrenheit = value * 9/5 + 32
 
    @property
    def fahrenheit(self):
        return self.__fahrenheit

    @fahrenheit.setter
    def fahrenheit(self, value):
        self.__fahrenheit = float(value)

t1 = Temperature(32)
print(t1.fahrenheit, t1.celsius)
t1.celsius=10
print(t1.fahrenheit, t1.celsius)