Garbage Collection
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import ctypes
import gc
def ref_count(address):
return ctypes.c_long.from_address(address).value
# loop the garbage collector and look for the object
def object_by_id(object_id):
for obj in gc.get_objects():
if id(obj) == object_id:
return "Object exists"
return "Not found"
class A:
def __init__(self):
self.b = B(self)
print('A: self: {0}, b:{1}'.format(hex(id(self)), hex(id(self.b))))
class B:
def __init__(self, a):
self.a = a
print('B: self: {0}, a:{1}'.format(hex(id(self)), hex(id(self.a))))
gc.disable()
my_var = A()
print(hex(id(my_var)))
print('a: \t{0}',format(hex(id(my_var))))
print('a.b: \t{0}',format(hex(id(my_var.b))))
print('b.a: \t{0}',format(hex(id(my_var.b.a))))
a_id = id(my_var)
b_id = id(my_var.b)
print('refcount(a) = {0}'.format(ref_count(a_id)))
print('refcount(b) = {0}'.format(ref_count(b_id)))
print('a: {0}'.format(object_by_id(a_id)))
print('b: {0}'.format(object_by_id(b_id)))
my_var = None
print('refcount(a) = {0}'.format(ref_count(a_id)))
print('refcount(b) = {0}'.format(ref_count(b_id)))
print('a: {0}'.format(object_by_id(a_id)))
print('b: {0}'.format(object_by_id(b_id)))
# turn on GC
gc.collect()
print('refcount(a) = {0}'.format(ref_count(a_id)))
print('refcount(b) = {0}'.format(ref_count(b_id)))
print('a: {0}'.format(object_by_id(a_id)))
print('b: {0}'.format(object_by_id(b_id)))
Python
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