[FIXED] How can I delete an instance of a class within that class?

Issue

I want to know how you can delete a instance within the class. I am trying del self, but it doesn't seem to work. Here's my code:

class Thing:

    def __init__(self):
        self.alive = True
        self.age = 0

    def update(self):
        self.age += 1

    def kill(self):
        if self.age >= 10:
            del self

    def all(self):
        self.update()
        self.kill()

things =  []

for i in range(0, 10):
    thing.append(Thing())

while True:
    for thing in things:
        thing.all()

I specifically want to delete the instance inside the class. I have also replaced del self with self = None, but this statement doesn't seem to have any effect. How can I do this?

Solution

You can't do quite what you're asking for. Python's del statement doesn't work like that. What you can do however, is mark your instance as dead (you already have an attribute for this!), and then later, filter the list of objects to drop the dead ones:

class Thing:
    def __init__(self):
        self.alive = True   # use this attribute!
        self.age = 0

    def update(self):
        self.age += 1

    def kill(self):
        if self.age >= 10:
            self.alive = False  # change it's value here rather than messing around with del

    def all(self):
        self.update()
        self.kill()

things =  []

for i in range(0, 10):
    things.append(Thing())

while True:
    for thing in things:
        thing.all()

    things = [thing for thing in things if thing.alive] # filter the list

Note that the loops at the end of this code run forever with no output, even after all the Thing instances are dead. You might want to modify that so you can tell what's going on, or even change the while loop to check if there's are any objects left in things. Using while things instead of while True might be a reasonable approach!

Answered By - Blckknght