Automatically setting getter, setter and deleter in python

Question

Ok I've been reading about using the @property decorator in Python rather than specific methods for getting, setting and deleting. Some example code is shown below.

class Person(object):

    def __init__(self):

        self._firstName = None
        self._lastName = None
        self._age = None

    @property
    def firstName(self): return self._firstName
    @firstName.setter
    def firstName(self, val): self._firstName = val
    @firstName.deleter
    def firstName(self): del self._firstName

    @property
    def lastName(self): return self._lastName
    @lastName.setter
    def lastName(self, val): self._lastName = val
    @lastName.deleter
    def lastName(self): del self._lastName

    @property
    def age(self): return self._age
    @age.setter
    def age(self, val): self._age = val
    @age.deleter
    def age(self): del self._age

Peter = Person()

Peter.firstName = 'Peter'
Peter.lastName = 'Smith'
Peter.age = 21

print ' '.join([Peter.firstName, Peter.lastName])

As you can see, the majority of the code in the example is devoted to defining the methods.

My question is whether there is a way to automatically assign the getter, setter and deleter for each of my variables? In my actual code I have a lot more variables and it seems like a lot of repetitive code setting each method.

I realise that for simple cases it may not strictly be necessary however I'd prefer to code the methods in now in case I ever decide to increase the complexity of the class.

Answer 1

Keep it simple.

If you have functions like that, just use a publicly accessible variable. That is:

class Person(object):
    def __init__(self):
        self.firstName = None
        self.lastName = None
        self.age = None

is perfectly fine. A better approach given the usage is to require the data as part of the constructor, thus:

class Person(object):
    def __init__(self, firstName, lastName, age):
        self.firstName = firstName
        self.lastName = lastName
        self.age = None

person = Person('Peter', 'Smith', 21)

If you are concerned about which name is which, you can always be specific:

person = Person(firstName='Peter', lastName='Smith', age=21)

In the future, if you need to make it more complex, you can add getters/setters where needed.

Another consideration is that given the constructor, you can create a string conversion function on the Person object:

def __str__(self):
    return ' '.join([self.firstName, self.lastName])

This then allows you to use it like:

person = Person(firstName='Peter', lastName='Smith', age=21)
print(person)

so you don't need to know how it is implemented internally.

Another consideration is that Chinese/Japanese names place the surname first, people can have multiple last names (esp. in Spain) and can have middle names.