When I define a function and patch it using the with statement it runs fine. Output: My understanding is that using the with statement would cause the __enter__ and __exit__ methods to be called on the patch object. So I thought that would be equivalent to doing this: The output from the some_func call is the same in this case:
Tag: contextmanager
Can we mix contextmanager decorator with __enter__() and __exit__() methods in another class inside the same with statement?
In python3.8 I’m very familiar with the traditional __enter__ and __exit__ magic methods but new to the @contextlib.contextmanager decorator. Is it possible to mix the two patterns inside a single with statement? The following (highly contrived) script should explain the problem more clearly. Is there a definition of ContextClass.enter_context_function() and ContextClass.exit_context_function() (I imagine something needs to change inside __init__ as
Conditional or optional context managers in with statement
Suppose I have some kind of context manager (from a third-party library) that I am using like so: But, suppose if there is no value for test_dt, the context manager should not run, but all of the remaining code should run, like so: Assume that lines_of_code here is 2-3 lines of code which are exactly identical, is there a cleaner
Why can’t a module be a context manager (to a ‘with’ statement)?
Suppose we have the following mod.py: and the following use of it: I get an error: According to the documentation the documentation the with statement should execute as follows (I believe it fails at step 2 and therefore truncate the list): The context expression (the expression given in the with_item) is evaluated to obtain a context manager. The context manager’s
Python How to force object instantiation via Context Manager?
I want to force object instantiation via class context manager. So make it impossible to instantiate directly. I implemented this solution, but technically user can still instantiate object. And context manager: Any better solution ? Answer If you consider that your clients will follow basic python coding principles then you can guarantee that no method from your class will be
How does pySerial implement the “with” statement without __enter__ and __exit__?
pySerial can be used with Python’s with statement like this: I tried to see exactly what it is pySerial does to make this work, but I couldn’t find an __enter__ or __exit__ function anywhere! I ran grep -e ‘(__enter__)|(__exit__)’ *.py from the pySerial directory, and grep didn’t find either function. How does pySerial do it? Edit: I also tried the