Hidden features of Python

Abstraction: Lesser-known Python language features and hidden tricks

Key points:

• Chaining comparison operators: 1 < x < 10 is valid Python syntax
• Decorators, descriptors, and __missing__ for advanced object customization
• In-place value swapping without temp variable: a, b = b, a
• Generator expressions vs list comprehensions; for/else clause executes when loop completes without break
• Mutable default argument danger: default args are evaluated once at function definition, not each call
• itertools, with statement, and ternary expressions (x if cond else y) among top hidden features

Connections: Python · Python Idioms · Metaprogramming

Source: http://stackoverflow.com/questions/101268/hidden-features-of-python?lq=1