When is a variable released from memory? [duplicate]

Question

Say I define a function, which builds a list, and then prints the items of the list one by one (no practical use, just an example:

import os

def build_and_print():
    thingy = os.walk('some directory')
    for i in thingy:
        print i

if __name__ == '__main__:
    build_and_print()

If the thingy that is built is very large it could take up a lot of memory, at what point will it be released from memory?

Does python store the variable thingy until the script is finished running or until the function that builds/uses it is finished running?

Answer 1

Once a Variable goes out of scope, it is collected by the garbage collector.

You can see the collector code here. Go to collect function, there comments explain the process well.