The document explains how to write log files in Python using the built-in logging module. It discusses the advantages of log files, including debugging, performance analysis, and error tracking, which help developers understand program behavior. An example is provided to illustrate how to create and write to a log file.

1. LOG file Writing

4. A log file in Python is a record of events generated by a program during its execution. It includes
messages, warnings, and errors that can be crucial for understanding the program’s behavior. Python
provides a built-in module called logging to facilitate easy logging.

5. Advantages of Log File in Python
● Debugging: Log files are invaluable during the debugging phase. They provide a detailed
history of events, making it easier to identify and rectify issues.
● Performance Analysis: By analyzing log files, developers can gain insights into the
performance of their applications. This includes execution times, resource usage, and potential
bottlenecks.
● Error Tracking: Log files help in tracking errors and exceptions, providing detailed information
about the context in which they occurred. This aids in fixing issues promptly.

6. Example 1: Creating and Writing Log File
import logging
logging.basicConfig(filename="gfg-
log.log",filemode="w",format="%(name)s → %
(levelname)s: %(message)s")
logging.warning("warning")
logger = logging.getLogger(__name__)
FileOutputHandler = logging.FileHandler('logs.log')
logger.addHandler(FileOutputHandler)
logger.warning("test.")