Python Academy · Lesson

The with Statement in Depth

Understand how with works and why it prevents resource leaks.

Introduction

The with statement guarantees setup and teardown code runs, even when exceptions occur.

with expr as var: — expr must return a context manager. var is bound to whatever __enter__ returns.

with open('/tmp/cm_test.txt','w') as f:
    f.write('hello')
print('file closed:', f.closed)