bearfrieze

Comprehensions in Python the Jedi way

by Bjørn Friese

Beautiful is better than ugly. Explicit is better than implicit.

-- The Zen of Python

I frequently deal with collections of things in the programs I write. Collections of droids, jedis, planets, lightsabers, starfighters, etc. When programming in Python, these collections of things are usually represented as lists, sets and dictionaries. Oftentimes, what I want to do with collections is to transform them in various ways. Comprehensions is a powerful syntax for doing just that. I use them extensively, and it's one of the things that keep me coming back to Python. Let me show you a few examples of the incredible usefulness of comprehensions.

tlack

// Matraka's source code decoded and beautified
// by @tlack
//
// Matraka is a 1005 byte Javascript "demo" by p01. It includes an 'evolving animation'
// and great dirty synth music. View here:
// 
// http://www.p01.org/releases/MATRAKA/matraka.png.html
//
// I fondly recall the demo scene of my youth, puzzling over the work of Future
// Creators and those guys. I was puzzled by this worked so I had to figure it

dcramer

from django.db.models.signals import post_init

def track_data(*fields):
    """
    Tracks property changes on a model instance.
    
    The changed list of properties is refreshed on model initialization
    and save.
    
    >>> @track_data('name')