Python class : getting started

I have never done any OO in Python, but I think I should. OO is good.
Maybe one day will shall say "there was a time where people believed in OO, hahaha what a bunch of losers, now we know that the right thing to do is.... (name your methodology)".

But in the meantime OO is better than Hashtables.

Minimalistic class:

class Pippo:
    name = "hello"

Unlike in Java, this doesn't work:

class Pippo:

there MUST be something inside a class.

Now you can do:
a = Pippo()

this is valid because Pippo has been defined.... if you do
a = Peppo()
you get an error because Peppo class is not defined.

If you do:
a = Pippo()
print a.name
hello

as expected, name was initialized and it's a Object variable, not a Class variable (I mean, it's not static):

a = Pippo()
b = Pippo()
a.name ="bla"
b.name = "mumble"

print a.name
bla
print b.name
mumble

Now let's do:
a.name = "ciao"
a.surname = "bello"
print a

print a.name
ciao

print a.surname
bello

so it's not necessary to declare a member of a class in order to use it. I don't like it, very error prone. I am VERY much in favor of VERY strict syntax.


So it's a MUCH better approach to use mainly Constructors to assign values to attributes:

class Pippo:
    def __init__(self, name, surname):
        self.name = name
        self.surname = surname

a = Pippo("alfa", "beta")

print a.name
alfa
print a.surname
beta


now you can define your classes in a module myclasses.py and then do:

from myclasses import Pippo