Python Contextlib Module
The contextlib module provides utilities for common tasks involving the with statement.
Importing the Module
import contextlibcontextmanager
The @contextmanager decorator is a generator-based factory for context managers. It lets you define a context manager using a simple generator function, instead of creating a class with __enter__ and __exit__ methods.
from contextlib import contextmanager
@contextmanager
def my_context():
print("Entering")
yield "value"
print("Exiting")
with my_context() as val:
print(f"Inside with {val}")
# Output:
# Entering
# Inside with value
# Exitingclosing
The closing() function returns a context manager that closes things upon completion of the block. This is useful for objects that have a close() method but don't support the context manager protocol.
from contextlib import closing
from urllib.request import urlopen
with closing(urlopen('http://www.python.org')) as page:
for line in page:
print(line)
breaksuppress
suppress(*exceptions) returns a context manager that suppresses any of the specified exceptions if they occur in the body of the with statement.
from contextlib import suppress
import os
with suppress(FileNotFoundError):
os.remove('somefile.tmp')redirect_stdout
Context manager for temporarily redirecting sys.stdout to another file-like object.
from contextlib import redirect_stdout
import io
f = io.StringIO()
with redirect_stdout(f):
print('foobar')
print('Got:', f.getvalue())
# Output: Got: foobar