Asked By – norman
Is there a way to begin a block of code with a with statement, but conditionally?
if needs_with(): with get_stuff() as gs: # do nearly the same large block of stuff, # involving gs or not, depending on needs_with()
To clarify, one scenario would have a block encased in the with statement, while another possibility would be the same block, but not encased (i.e., as if it wasn’t indented)
Initial experiments of course give indentation errors..
Now we will see solution for issue: Conditional with statement in Python
If you want to avoid duplicating code and are using a version of Python prior to 3.7 (when
contextlib.nullcontext was introduced) or even 3.3 (when
contextlib.ExitStack was introduced), you could do something like:
class dummy_context_mgr(): def __enter__(self): return None def __exit__(self, exc_type, exc_value, traceback): return False
import contextlib @contextlib.contextmanager def dummy_context_mgr(): yield None
and then use it as:
with get_stuff() if needs_with() else dummy_context_mgr() as gs: # do stuff involving gs or not
You alternatively could make
get_stuff() return different things based on