Why is it considered good practice to limit the length of a line in code to about 79 characters?

Limiting the length of a line of code to about 79 characters is a recommendation from PEP 8, the official Python coding style. The main reasons:

• Readability: shorter lines are easier to perceive visually, especially when viewing code on different devices.
• Tool compatibility: many editors and terminals default to a width of about 80 characters.
• Simplified code comparison: when using version control systems and viewing diffs, long lines can complicate change analysis.
• Support for multiple windows and panels: developers often work with multiple files or windows, and limiting line length helps to comfortably place code.

Example:

# Good
if user.is_active and user.has_permission:
    perform_action()

# Bad (too long line)
if user.is_active and user.has_permission and user.account_balance > 0 and user.subscription.is_valid:
    perform_action()