All 15 Logging questions
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What are Python's five standard logging severity levels, from lowest to highest? What does logging.basicConfig() do, and what are its common pitfalls? How do you format log output to include the timestamp, logger name, level, and message? What is the relationship between Logger, Handler, Formatter, and Filter in the logging module? Why is it recommended to use logging.getLogger(__name__) instead of the root logger in library and module code? How do you configure logging using a dictionary via logging.config.dictConfig? How do you include structured context (like a request ID) in every log message using LoggerAdapter or extra? What's the difference between propagate=True and propagate=False on a logger? What's the danger of using %-style, f-string, or .format() interpolation directly in a log call's message argument versus lazy % substitution? How do RotatingFileHandler and TimedRotatingFileHandler prevent log files from growing unbounded?
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Why should you use the logging module instead of print() for diagnostic output?

Beginner

Answer

logging supports severity levels (DEBUG, INFO, WARNING, ERROR, CRITICAL), can be routed to multiple destinations (console, files, network) simultaneously, includes timestamps and context automatically, and can be toggled or filtered without editing code -- print() offers none of this and is hard to disable in production.
import logging

logging.basicConfig(level=logging.INFO)
logging.info('Application started')
logging.warning('Config value missing, using default')
Real-world example A production web service logs request errors to a file and sends CRITICAL-level logs to a monitoring alert system, something print() statements can't do.

Common follow-ups: What are the five standard logging levels in order?;How do you disable logging below a certain level?

Debugging & Profiling;Exception Handling
All 15 Logging questions