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Functions & basics

Reusable building blocks — parameters, returns, scope, and clear function design.

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Functions & basics easy

How to Write a Context Manager Class in Python

Define a class with __enter__ and __exit__ to manage file resources safely using the with statement.

context-manager with-statement resource-management
Python 
class FileReader:
    def __init__(self, filename, mode="r"):
        self.filename = filename
        self.mode = mode
        self.file = None

    def __enter__(self):
        self.file = open(self.filename, self.mode)
        return self.file

    def __exit__(self, exc_type, exc_val, exc_tb):
        if self.file…
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