Python for ops check

Ten questions on the Python every operations engineer uses.

Pass mark: 70% · 10 questions

1. 1. What does f"cpu={cpu:.0f}%" do when cpu = 87.5?

   Prints cpu=88% — formats with no decimalsCrashes — invalid syntaxPrints cpu=87.5% unchanged

2. 2. Safest way to read a key that might be missing from dict d?

   d['key']d.get('key', default)d.key

3. 3. What does line.split()[2] return for '2026-08-12 10:31 ERROR db down'?

   '10:31''ERROR''db'

4. 4. Why open files with `with open(...) as f:`?

   It is fasterThe file closes automatically, even if an error occursIt reads the whole file into memory

5. 5. json.load vs json.loads?

   load reads a FILE object, loads parses a STRINGThey are identicalloads is the newer name

6. 6. What exit code should an ops script use to make CI fail?

   0Any non-zero value, e.g. 1-1 only

7. 7. [s['name'] for s in fleet if s['cpu'] > 80] is called a…

   lambdalist comprehensiongenerator class

8. 8. In a retry loop, why grow the delay each attempt (backoff)?

   Python requires itTo avoid hammering an already-struggling serviceTo use less memory

9. 9. Select ALL true statements about virtual environments:

   They isolate dependencies per projectpip installs inside an active venv don't touch system PythonOne venv is shared by all projects on a machine

10. 10. How do you read a Python traceback?

    Top-down — the first line is the errorBottom-up — the last line names the error, lines above locate itOnly the middle matters