Interview Q&A / Python
Python interview questions
Lists, dictionaries, generators, decorators and the Python questions asked in service-company and data roles.
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- Why do we use the with statement when working with files?
with guarantees the file is closed when the block ends, even if an exception occurs. It works through a context manager, an object with __enter__ and __exit__ methods, so cleanup does not depend on remembering to call close().
BeginnerQuick answer1 min read - How do you write your own context manager in Python?
Either write a class with __enter__ and __exit__ methods, or write a generator function decorated with @contextlib.contextmanager that yields once. Code before the yield is setup and code after it is cleanup, which should sit in a finally block.
IntermediateQuick answer1 min read