TRogier TRogier - 3 months ago 5
Python Question

Python classes: method has same name as property

I'm constructing a class Heating. Every instance of this class has the property 'temperature'. It's mandatory that Heating also supports the method temperature() that prints the property 'temperature' as an integer.

When I call the method temperature() I get the error 'int' object is not callable because self.temperature is already defined as an integer.

How do I solve this?

code:

class Heating:
"""
>>> machine1 = Heating('radiator kitchen', temperature=20)
>>> machine2 = Heating('radiator living', minimum=15, temperature=18)
>>> machine3 = Heating('radiator bathroom', temperature=22, minimum=18, maximum=28)
>>> print(machine1)
radiator kitchen: current temperature: 20.0; allowed min: 0.0; allowed max: 100.0
>>> machine2
Heating('radiator living', 18.0, 15.0, 100.0)
>>> machine2.changeTemperature(8)
>>> machine2.temperature()
26.0
>>> machine3.changeTemperature(-5)
>>> machine3
Heating('radiator bathroom', 18.0, 18.0, 28.0)
"""
def __init__(self, name, temperature = 10, minimum = 0, maximum = 100):
self.name = name
self.temperature = temperature
self.minimum = minimum
self.maximum = maximum

def __str__(self):
return '{0}: current temperature: {1:.1f}; allowed min: {2:.1f}; allowed max: {3:.1f}'.format(self.name, self.temperature, self.minimum, self.maximum)

def __repr__(self):
return 'Heating(\'{0}\', {1:.1f}, {2:.1f}, {3:.1f})'.format(self.name, self.temperature, self.minimum, self.maximum)

def changeTemperature(self, increment):
self.temperature += increment

if self.temperature < self.minimum:
self.temperature = self.minimum

if self.temperature > self.maximum:
self.temperature = self.maximum

def temperature(self):
return self.temperature




# testen van het programma
if __name__ == '__main__':
import doctest
doctest.testmod()

Answer

You can't have both a method and an attribute with the same name. Methods are attributes too, albeit ones that you can call.

Just rename the attribute to something else. You could use _temperature:

def __init__(self, name, temperature = 10, minimum = 0, maximum = 100):
    self.name = name
    self._temperature = temperature
    self.minimum = minimum
    self.maximum = maximum

def __str__(self):
    return '{0}: current temperature: {1:.1f}; allowed min: {2:.1f}; allowed max: {3:.1f}'.format(self.name, self._temperature, self.minimum, self.maximum)

def __repr__(self):
    return 'Heating(\'{0}\', {1:.1f}, {2:.1f}, {3:.1f})'.format(self.name, self._temperature, self.minimum, self.maximum)

def changeTemperature(self, increment):
    self._temperature += increment

    if self.temperature < self.minimum:
        self._temperature = self.minimum

    if self.temperature > self.maximum:
        self._temperature = self.maximum

def temperature(self):
    return self._temperature

Now your class has both _temperature (the integer) and temperature() (the method); the latter returns the former.

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