Avoid Memory leak

Question

Below I create a list of Any instances, then I modify this list and finally I randomly chose some elements of this list in order to create a new list.

from random import choice
import copy

class Any():
    def __init__(self,x):
       self.x=x

    def modify (self):
        self.x += choice([0,1])
        return self

def create_new_list (old_list):
    new_list = [copy.deepcopy(old_list[choice(range(len(old_list)))]) for i in range(len(old_list))]
    return new_list


a = [Any(0),Any(19),Any(3),Any(10)] # Create the original list
for iteration in xrange(20):
    [i.modify() for i in a]
    a = create_new_list(a)

1. I am obliged to copy the elements of the old list as I then want to modify them independently. Is it correct?

2. Because of this system, I am creating, at every loop new instances of Any that will be kept in memory yielding to an issue of memory leak. Is it correct?

3. How can I avoid this?

   3a) What if I add

   del old_list

   at the end of the function create_new_list?

   3b) Or should I add

   [del(i) for i in old_list]

   del old_list

   at the end of the create_new_list?

   3c) Is there another, more efficient solution?

Answer 1

In your case, no, you don't need to copy anything.

Furthermore, you don't need to explicitly deallocate anything. Things will be garbage-collected when they are no longer referenced.