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.

mrdoob

www.example.com CNAME c.storage.googleapis.com

create www.example.com bucket.

gsutil setdefacl "public-read" gs://www.example.com
gsutil setwebcfg -m index.html -e 404.html gs://www.example.com

from the folder with the local copy:

gsutil -m cp -r -z html,js,css * gs://www.example.com

mtigas

#!/usr/bin/python
#
# Copyright 2009 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#

dound

import urllib2, urllib

class RecaptchaResponse(object):
    def __init__(self, is_valid, error_code=None):
        self.is_valid = is_valid
        self.error_code = error_code

def submit (recaptcha_challenge_field,
            recaptcha_response_field,
            private_key,