Luke Van In lukevanin

Implementation of the Luhn 10 algorithm to check validity of credit card numbers. See http://en.wikipedia.org/wiki/Luhn_algorithm for details on the algorithm.

var validCreditCard = function(a,b,c,d,e){for(d=+a[b=a.length-1],e=0;b--;)c=+a[b],d+=++e%2?2*c%10+(c>4):c;return!(d%10)};

validCreditCard('378282246310005'); //=> true
validCreditCard('378282246310006'); //=> false

// some numbers to test with
// 378282246310005 371449635398431 378734493671000

Accessing an API using CoreData's NSIncrementalStore

Note: the original location of this article is on my blog, however, it is posted here too for better readability.

In this article, we will see how to use Core Data for accessing your API. We will use the Bandcamp API as our running example. I've only been experimenting with this code for a few days, so there might be mistakes in there.

Git

Global Settings

Related Setup: https://gist.github.com/hofmannsven/6814278
Related Pro Tips: https://ochronus.com/git-tips-from-the-trenches/
Interactive Beginners Tutorial: http://try.github.io/
Git Cheatsheet by GitHub: https://services.github.com/on-demand/downloads/github-git-cheat-sheet/

Reminder

Press minus + shift + s and return to chop/fold long lines!

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.


	/**
	Copyright (C) 2011 Evan Long

	Permission is hereby granted, free of charge, to any person obtaining a copy of
	this software and associated documentation files (the "Software"), to deal in
	the Software without restriction, including without limitation the rights to
	use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
	of the Software, and to permit persons to whom the Software is furnished to do
	so, subject to the following conditions:

	#!/bin/bash

	#
	# This is a Mac OSX shell script, you can simply double-click to start it.
	#

	# This is where you downloaded the AIR SDK from http://labs.adobe.com/downloads/air3-3.html
	AIR_SDK="/Applications/Adobe/AIR SDK/AIR SDK 3.3b3"

	# iOS 5.0

	Latency Comparison Numbers (~2012)
	----------------------------------
	L1 cache reference 0.5 ns
	Branch mispredict 5 ns
	L2 cache reference 7 ns 14x L1 cache
	Mutex lock/unlock 25 ns
	Main memory reference 100 ns 20x L2 cache, 200x L1 cache
	Compress 1K bytes with Zippy 3,000 ns 3 us
	Send 1K bytes over 1 Gbps network 10,000 ns 10 us
	Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD

	#########################
	# .gitignore file for Xcode4 and Xcode5 Source projects
	#
	# Apple bugs, waiting for Apple to fix/respond:
	#
	# 15564624 - what does the xccheckout file in Xcode5 do? Where's the documentation?
	#
	# Version 2.6
	# For latest version, see: http://stackoverflow.com/questions/49478/git-ignore-file-for-xcode-projects
	#

	UIImage TintImageWithTintColor(UIImage image, UIColor *tintColor) {
	// Huge props to http://stackoverflow.com/questions/3514066/how-to-tint-a-transparent-png-image-in-iphone

	UIGraphicsBeginImageContext(image.size);
	CGContextRef context = UIGraphicsGetCurrentContext();

	CGContextTranslateCTM(context, 0, image.size.height);
	CGContextScaleCTM(context, 1.0, -1.0);

	CGRect rect = (CGRect){ CGPointZero, image.size };

	#import <UIKit/UIKit.h>
	#import <ImageIO/ImageIO.h>
	#import <MobileCoreServices/MobileCoreServices.h>

	static UIImage *frameImage(CGSize size, CGFloat radians) {
	UIGraphicsBeginImageContextWithOptions(size, YES, 1); {
	[[UIColor whiteColor] setFill];
	UIRectFill(CGRectInfinite);
	CGContextRef gc = UIGraphicsGetCurrentContext();
	CGContextTranslateCTM(gc, size.width / 2, size.height / 2);