I believe this has already been answered by other users before me, so I only add it for the sake of completeness: the with statement simplifies exception handling by encapsulating common preparation and cleanup tasks in so-called context managers. More details can be found in PEP 343. For instance, the open statement is a context … Read more
Using these magic methods (__enter__, __exit__) allows you to implement objects which can be used easily with the with statement. The idea is that it makes it easy to build code which needs some ‘cleandown’ code executed (think of it as a try-finally block). Some more explanation here. A useful example could be a database … Read more
It is possible in Python 3 since v3.1 and Python 2.7. The new with syntax supports multiple context managers: with A() as a, B() as b, C() as c: doSomething(a,b,c) Unlike the contextlib.nested, this guarantees that a and b will have their __exit__()‘s called even if C() or it’s __enter__() method raises an exception. You … Read more