Python 'with' not deleting object

Question

Trying to properly delete a Python object. I'm creating an object and then supposedly deleting it with a 'with' statement. But when I do a print out after the 'with' statement is closed.... the object is still there:

class Things(object):
   def __init__(self, clothes, food, money):
       self.clothes = clothes
       self.food = food
       self.money = money

   def __enter__(self):
       return self

   def __exit__(self, exc_type, exc_val, exc_tb):
       print('object deleted')

with Things('socks','food',12) as stuff:
    greg = stuff.clothes
    print(greg)


print(stuff.clothes)

returns :

socks
object deleted
socks

Answer 1

Python's with statement is not about deleting objects - it's about resource management. The __enter__ and __exit__ methods are for you to supply resource initialization and destruction code i.e. you may choose to delete something there, but there is no implicit deletion of objects. Have a read of this with article to get a better understanding of how to use it.

The object stays in scope after the with statement. You could call del on it if that's what you want. Since it's in scope you can query it after it's underlying resources have been closed. Consider this psuedo code:

class DatabaseConnection(object):
  def __init__(self, connection):
    self.connection = connection
    self.error = None

  def __enter__(self):
    self.connection.connect()

  def __exit__(self, exc_type, exc_val, exc_tb):
    self.connection.disconnect()

  def execute(self, query):
    try
      self.connection.execute(query)
    except e:
      self.error = e

with DatabaseConnection(connection) as db:
  db.execute('SELECT * FROM DB')
if db.error:
  print(db.error)

del db

We wouldn't want to keep a database connection hanging around longer than we need (another thread/client might need it), so instead we allow the resource to be freed (implicitly at the end of the with block), but then we can continue to query the object after that. I've then added an explicit del to tell the runtime that the code is finished with the variable.