ExitStack

contextlib

class · Added in 3.3 (source)

Context manager for dynamic management of a stack of exit callbacks.

For example:
    with ExitStack() as stack:
        files = [stack.enter_context(open(fname)) for fname in filenames]
        # All opened files will automatically be closed at the end of
        # the with statement, even if attempts to open files later
        # in the list raise an exception.

© Python Software Foundation. PSF License Version 2 · Official docs ↗

Members of ExitStack

c

callback: Registers an arbitrary callback and arguments.
close: Immediately unwind the context stack.

e

enter_context: Enters the supplied context manager.

p

pop_all: Preserve the context stack by transferring it to a new instance.
push: Registers a callback with the standard __exit__ method signature.

1 Example

link / history / report

>>> from contextlib import ExitStack
>>> stack = ExitStack()
>>> with stack:
...     stack.callback(print, "Callback: from first context")
...     print("Leaving first context")
...
Leaving first context
Callback: from first context
>>> with stack:
...     stack.callback(print, "Callback: from second context")
...     print("Leaving second context")
...
Leaving second context
Callback: from second context
>>> with stack:
...     stack.callback(print, "Callback: from outer context")
...     with stack:
...         stack.callback(print, "Callback: from inner context")
...         print("Leaving inner context")
...     print("Leaving outer context")
...
Leaving inner context
Callback: from inner context
Callback: from outer context
Leaving outer context

from the Python docs