What are context managers? Why use them?

Context managers in Python are constructs that manage resources, ensuring their proper opening and closing. They implement the __enter__ and __exit__ methods, allowing them to be used with the with keyword.

Why use them:

• Guarantee resource release (files, network connections, locks) even in case of errors.
• Simplify code, making it more readable and safe.

Example:

with open('file.txt', 'r') as f:
    data = f.read()
# the file is automatically closed after exiting the with block

Here, open returns a context manager that opens the file and guarantees its closure.