What are the lesser-known but useful features of the Python programming language?
- Try to limit answers to Python core.
- One feature per answer.
- Give an example and short description of the feature, not just a link to documentation.
- Label the feature using a title as the first line.
Quick links to answers:
- Argument Unpacking
- Braces
- Chaining Comparison Operators
- Decorators
- Default Argument Gotchas / Dangers of Mutable Default arguments
- Descriptors
- Dictionary default
.getvalue - Docstring Tests
- Ellipsis Slicing Syntax
- Enumeration
- For/else
- Function as iter() argument
- Generator expressions
import this- In Place Value Swapping
- List stepping
__missing__items- Multi-line Regex
- Named string formatting
- Nested list/generator comprehensions
- New types at runtime
.pthfiles- ROT13 Encoding
- Regex Debugging
- Sending to Generators
- Tab Completion in Interactive Interpreter
- Ternary Expression
try/except/else- Unpacking+
print()function withstatement