G.Grandes ggrandes

Notas tomadas durante el #SOSZ18

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.

	# Custom history configuration
	# Run script using:
	# chmod u+x better_history.sh
	# sudo su
	# ./better_history.sh

	echo ">>> Starting"
	echo ">>> Loading configuration into /etc/bash.bashrc"
	echo "HISTTIMEFORMAT='%F %T '" >> /etc/bash.bashrc
	echo 'HISTFILESIZE=-1' >> /etc/bash.bashrc

	#!/usr/bin/env bash
	#
	# Author: Markus (MawKKe) [email protected]
	# Date: 2018-03-19
	#
	#
	# What?
	#
	# Linux dm-crypt + dm-integrity + dm-raid (RAID1)
	#

	import com.mongodb.BasicDBObject;
	import com.mongodb.util.JSON;
	import org.jivesoftware.smack.SmackException;
	import org.jivesoftware.smack.StanzaListener;
	import org.jivesoftware.smack.XMPPException;
	import org.jivesoftware.smack.filter.StanzaTypeFilter;
	import org.jivesoftware.smack.packet.ExtensionElement;
	import org.jivesoftware.smack.packet.StandardExtensionElement;
	import org.jivesoftware.smack.packet.Stanza;
	import org.jivesoftware.smack.roster.Roster;

	/**
	* Encrypts plaintext using AES-GCM with supplied password, for decryption with aesGcmDecrypt().
	* (c) Chris Veness MIT Licence
	*
	* @param {String} plaintext - Plaintext to be encrypted.
	* @param {String} password - Password to use to encrypt plaintext.
	* @returns {String} Encrypted ciphertext.
	*
	* @example
	* const ciphertext = await aesGcmEncrypt('my secret text', 'pw');

	/**
	* Returns PBKDF2 derived key from supplied password.
	*
	* Stored key can subsequently be used to verify that a password matches the original password used
	* to derive the key, using pbkdf2Verify().
	*
	* @param {String} password - Password to be hashed using key derivation function.
	* @param {Number} [iterations=1e6] - Number of iterations of HMAC function to apply.
	* @returns {String} Derived key as base64 string.
	*

	/**
	* Returns SHA-256 hash from supplied message.
	*
	* @param {String} message.
	* @returns {String} hash as hex string.
	*
	* @example
	* sha256('abc').then(hash => console.log(hash));
	* const hash = await sha256('abc');
	*/

	#!/boot/bzImage

	# Linux kernel userspace initialization code, translated to bash
	# (Minus floppy disk handling, because seriously, it's 2017.)
	# Not 100% accurate, but gives you a good idea of how kernel init works
	# GPLv2, Copyright 2017 Hector Martin <[email protected]>
	# Based on Linux 4.10-rc2.

	# Note: pretend chroot is a builtin and affects the current process
	# Note: kernel actually uses major/minor device numbers instead of device name

	#!/usr/bin/env python3
	#
	# Decompressor/compressor for files in Mozilla's "mozLz4" format. Firefox uses this file format to
	# compress e. g. bookmark backups (*.jsonlz4).
	#
	# This file format is in fact just plain LZ4 data with a custom header (magic number [8 bytes] and
	# uncompressed file size [4 bytes, little endian]).
	#
	# This Python 3 script requires the LZ4 bindings for Python, see: https://pypi.python.org/pypi/lz4
	#