Josh Ashby JoshAshby

Comprehensions in Python the Jedi way

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

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.

##Intro

Generator frameworks spend way too much time creating obscure and pointless DSL syntax just to make the code trendy and cute. This generator comes in the form of pure ruby, instantiates real model objects (which fire their pre-, post- and other hooks appropriately), and still allows for a simple syntax to override parameters of generated objects.

Standard Ruby syntax allows for easier adoption by new programmers and reinforces ruby paradigms, instead of breaking them down with a cute, often incomplete, and entirely superfluous DSL syntax.

Specific complaints against existing frameworks:

Rails fixtures: definition syntax (yaml) doesn't provide a powerful enough interface to rapidly creating objects.
FactoryGirl: Factories are evaluated at load-time, making some factories just awful to define. No further comment on DSLs.

	var Redis = require('ioredis');

	var redis = new Redis({
	host: "nodesydney.wiftycloud.com",
	password: "7884b8baaa49fbcb48f17ad2a146"
	});

	async function main() {
	// write an event to stream 'events', setting 'key1' to 'value1'
	await redis.sendCommand(

	#!/bin/sh

	curl 'https://giphy.com/page/2?next=2017-12-01%2004%3A15%3A01&amp%3Bis=1&is=1&json=true' -o gipyurls.json
	jq .[].gifs[].images.original.url gipyurls.json \|cut -d / -f 5 \| parallel -j 20 --gnu curl https://media2.giphy.com/media/{}/giphy.gif -o {}.gif


	parallel -j 20 --gnu "ffmpeg -f gif -i {} {}.h264.mp4" ::: *.gif
	parallel -j 20 --gnu "ffmpeg -f gif -i {} -c:v libx265 {}.h265.mp4" ::: *.gif
	parallel -j 20 --gnu "ffmpeg -f gif -i {} -c:v libvpx {}.vp8.webm" ::: *.gif
	parallel -j 20 --gnu "ffmpeg -f gif -i {} -c:v libvpx-vp9 {}.vp9.webm" ::: *.gif

	// ==UserScript==
	// @name Make Medium Readable Userscript
	// @namespace http://make.medium.readable.again
	// @version 0.1
	// @description https://github.com/thebaer/MMRA
	// @author luke3butler (Credits to Matt Baer)
	// @match :///*
	// @grant none
	// ==/UserScript==

	using System;
	using System.Collections;
	using System.Collections.Generic;
	using UnityEngine;

	public class OcclusionBase : MonoBehaviour {

	public bool isVisible { get; set; }
	public DateTime lastSeen { get; set; }
	}

	ctrl_table = {
	sends_escape = true,
	last_mods = {}
	}

	control_key_timer = hs.timer.delayed.new(0.15, function()
	ctrl_table["send_escape"] = false
	-- log.i("timer fired")
	-- control_key_timer:stop()
	end

	"""
	Minimal character-level Vanilla RNN model. Written by Andrej Karpathy (@karpathy)
	BSD License
	"""
	import numpy as np

	# data I/O
	data = open('input.txt', 'r').read() # should be simple plain text file
	chars = list(set(data))
	data_size, vocab_size = len(data), len(chars)

	# Hello, and welcome to makefile basics.
	#
	# You will learn why `make` is so great, and why, despite its "weird" syntax,
	# it is actually a highly expressive, efficient, and powerful way to build
	# programs.
	#
	# Once you're done here, go to
	# http://www.gnu.org/software/make/manual/make.html
	# to learn SOOOO much more.

	class AddressBook

	def contacts
	@contacts \|\|= []
	end

	def self.load_from_path(path)
	# Create a new AddressBook instance
	address_book = self.new
	# Create a new AddressBookDSL instance