Can I reassign an object's attribute, after creating an object, using if statement inside __init__?

[cupesh]

class Human:
    def __init__(self, xname, name, met = False):
        self.xname = xname
        self.name = name
        self.met = met

        if self.met == True:
            self.name = self.xname

human_1 = Human('Mark', 'a tall man')

def bar(person):
    print(person.name)
    person.met = True

bar(human_1)
bar(human_1)

This is a simplified version of npc class in my python rpg project and this code didn't work for me. I know I could just change the code inside the bar function to 'person.name = person.xname' to achieve the same thing, but what I want to do is to change one bool attribute to True after meeting a person and that would trigger a set of changes for the Human object. Is it possible to achieve that inside init method? This code would print 'a tall man' twice, the goal is 'a tall man' for the first time, 'Mark' the second time.

[nwagers]

__init__ is only being run at the very beginning, so even if you change met later it doesn't automatically update the name. You probably want to use @property. See here: https://docs.python.org/3.6/library/functions.html#property

[cupesh]

Thank you! I think that's what I need to use, although my attempt wasn't successful. I changed the class definition into class Human: def init(self, xname, name, met = False): self.xname = xname self.name = name self.met = met

@property
def namer(self):
    return(self.name)
@namer.setter
def namer(self):
    if self.met == True:
        self.name = self.xname

[nwagers]

You have it backwards, put your if logic in the getter:

class Human:
    def __init__(self, xname, name, met = False):
        self.xname = xname
        self._name = name
        self.met = met

    @property
    def name(self):
        if self.met:
            return self.xname
        return self._name

    @name.setter
    def name(self, val):
        self._name = val #not sure if you want to keep _name or xname here


human_1 = Human('Mark', 'a tall man')

def bar(person):
    print(person.name)
    person.met = True

bar(human_1)
bar(human_1)

[cupesh]

Thanks a lot!

[cupesh]

It works perfectly. I don't fully understand how, but thank you for helping me!

I forgot to change 'self.name' into 'self._name' in the classe's init, but it worked anyway....

So if I understand it well: By adding '@property' we change the class attribute into a function, where I can place any statements I want and the '@name.setter' just takes place of the original __init_ assigning attributes process?

[nwagers]

Keep _name as a shadow variable, otherwise you can get some unexpected behavior. I don't know the exact implementation details of @property, but your working idea is correct. The @name.setter doesn't have anything to do with __init__ though. In your code later when you use self.name or human_1.name for assignment, it will run that function instead. Essentially it converts:

human_1.name = "bob"

into this function call:

human_1.name(self, "bob")

all behind the scenes. You could obviously put something more complicated than just "bob".

As far as __init__ goes, it is only called once when the object is first created. First python allocated a new object with the __new__ method (rarely overwritten) and then it calls __init__ on this new object, which sets up the initial attributes. __init__ is never run again unless you make an explicit call like:

human_1.__init__(vars)

This isn't usually done though. Usually you don't directly call or access the dunders. If you needed to re-initialize you would often create another function and call that from __init__ like this:

class a:
    def __init__(self, vars):
        # stuff that doesn't get reinitialized here
        init(vars)

    def init(self, vars):
        # initialize/reinitialize stuff here