Python 2.6: Class inside a Class?

Question

Hey everyone, my problem is that im trying to figure out how to get a class INSIDE another class.

What I am doing is I have a class for an Airplane with all its statistics as to how fast it can fly, how far it can go, fuel consumption, and so on. Then I have a Flight Class which is all the details about the flight: Distance, starting location and time, ending location and time, duration, and so on.

But I realized that each airplane has multiple flights, so why not put all the flight data into the airplane class? Although how do i put a class INTO another class so i can call something like this:

Player1.Airplane5.Flight6.duration = 5 hours

Ive somewhat done it with the airplane class, but when i go to save the information (listing everything out into a text document), all it gives me is the Hex location of the data and not the actual strings.

class Player (object):#Player Class to define variables
    '''Player class to define variables'''

    def __init__ (self, stock = 0, bank = 200000, fuel = 0, total_flights = 0, total_pax = 0):
        self.stock = stock
        self.bank = bank
        self.fuel = fuel
        self.total_flights = total_flights
        self.total_pax = total_pax
        self.Airplanes = Airplanes
        self.flight_list = flight_list

Is there a way to put a class inside a class? or will i need to make one super Player class which handles all the information which im using other classes for?

Answer 1

I think you are confusing objects and classes. A class inside a class looks like this:

class Foo(object):
    class Bar(object):
        pass

>>> foo = Foo()
>>> bar = Foo.Bar()

But it doesn't look to me like that's what you want. Perhaps you are after a simple containment hierarchy:

class Player(object):
    def __init__(self, ... airplanes ...) # airplanes is a list of Airplane objects
        ...
        self.airplanes = airplanes
        ...

class Airplane(object):
    def __init__(self, ... flights ...) # flights is a list of Flight objects
        ...
        self.flights = flights
        ...

class Flight(object):
    def __init__(self, ... duration ...)
        ...
        self.duration = duration
        ...

Then you can build and use the objects thus:

player = Player(...[
    Airplane(... [
        Flight(...duration=10...),
        Flight(...duration=15...),
        ] ... ),
    Airplane(...[
        Flight(...duration=20...),
        Flight(...duration=11...),
        Flight(...duration=25...),
        ]...),
    ])

player.airplanes[5].flights[6].duration = 5

Answer 2

class Second:
    def __init__(self,data):
        self.data = data

class First:
    def SecondClass(self,data):
        return Second(data)

FirstClass = First()
SecondClass = FirstClass.SecondClass('now you see me')
print SecondClass.data

Answer 3

It sounds like you are talking about aggregation. Each instance of your player class can contain zero or more instances of Airplane, which, in turn, can contain zero or more instances of Flight. You can implement this in Python using the built-in list type to save you naming variables with numbers.

class Flight(object):

    def __init__(self, duration):
        self.duration = duration


class Airplane(object):

    def __init__(self):
        self.flights = []

    def add_flight(self, duration):
        self.flights.append(Flight(duration))


class Player(object):

    def __init__ (self, stock = 0, bank = 200000, fuel = 0, total_pax = 0):
        self.stock = stock
        self.bank = bank
        self.fuel = fuel
        self.total_pax = total_pax
        self.airplanes = []


    def add_planes(self):
        self.airplanes.append(Airplane())



if __name__ == '__main__':
    player = Player()
    player.add_planes()
    player.airplanes[0].add_flight(5)