Could someone explain to me, how to call the move method with the variable RIGHT
>>> myMissile = MissileDevice(myBattery) # looks like you need a battery, don't know what that is, you figure it out.
>>> myMissile.move(MissileDevice.RIGHT)
If you have programmed in any other language with classes, besides python, this sort of thing
class Foo:
bar = "baz"
is probably unfamiliar. In python, the class is a factory for objects, but it is itself an object; and variables defined in its scope are attached to the class, not the instances returned by the class. to refer to bar
, above, you can just call it Foo.bar
; you can also access class attributes through instances of the class, like Foo().bar
.
Im utterly baffled about what 'self' refers too,
>>> class Foo:
... def quux(self):
... print self
... print self.bar
... bar = 'baz'
...
>>> Foo.quux
<unbound method Foo.quux>
>>> Foo.bar
'baz'
>>> f = Foo()
>>> f.bar
'baz'
>>> f
<__main__.Foo instance at 0x0286A058>
>>> f.quux
<bound method Foo.quux of <__main__.Foo instance at 0x0286A058>>
>>> f.quux()
<__main__.Foo instance at 0x0286A058>
baz
>>>
When you acecss an attribute on a python object, the interpreter will notice, when the looked up attribute was on the class, and is a function, that it should return a "bound" method instead of the function itself. All this does is arrange for the instance to be passed as the first argument.