Context Managers

🔄 Context Managers

A context manager is used to manage resources automatically, such as files, database connections, or network connections.

The most common way to use one is with the with statement.

📂 Using with

Instead of manually opening and closing a file:

file = open("data.txt", "r")

content = file.read()

file.close()

We can use a context manager:

with open("data.txt", "r") as file:
    content = file.read()

Python automatically closes the file when the with block finishes.

🔹 Creating a Context Manager

A class can act as a context manager using:

__enter__()
__exit__()

Example:

class MyContext:
    def __enter__(self):
        print("Entering")

    def __exit__(self, exc_type, exc_value, traceback):
        print("Exiting")

with MyContext():
    print("Inside")

Entering
Inside
Exiting

Here:

__enter__() → Runs when entering the with block
__exit__()  → Runs when leaving the with block

with → Setup → Use → Cleanup automatically 🔄