Chrome Extensions – Basics – Manifest

• Run a custom script on the page
• Can access DOM elements
• Cannot interact with JavaScript variables
  • Use "messages" to communicate back and forth

• Volume
• Variety
• Velocity

• HDFS
  • Hadoop
  • Distributed
  • File
  • System
• Designed to store very large files with
  • Streaming data access
  • clusters of commodity hardware
• Not suitable for small files

• Programming model and an associated implementation for processing and generating large data sets with a
  • Parallel
  • Distributed Algorithm on a
  • Cluster (HDFS)
• Single Reducer (multiple slows down the process with sorting and shuffling)

• map (InputKey, InputValue) => Set of (IntermediateKey, IntermediateValue)
• ex) {0, "Twinkle Twinkle Little Star"} =>
  • {"Little", 1}
  • {"Star", 1}
  • {"Twinkle", (1,1)}
• reduce (IntermediateKeys, IntermediateValues) => Set of (OutputKey, OutputValue)
• ex)
  • {"Little", 1} => {"Little", 1}
  • {"Star", 1} => {"Star", 1}
  • {"Twinkle", (1,1)} => {"Twinkle", 2}

• Hadoop website
• Spark website

• R is an open source implementation of S
• Great for numerical and graphical analysis
• Is a language and an environment
• Cross platform support
• active development and large community
• FREE!

• Load up data from
  • File-based data
  • Web-based data
  • Databases (using RODBC extension)
  • ...the list goes on
• Clean, transform, and merge data
• Visualize it using R's comprehensive set of graphing utilities

• Visit these resources
  • R project page
  • R Studio
  • R by example
  • R graphics
  • R-bloggers machine learning
  • R-Bloggers in general

• Programmers spend 30% creating code, 70% maintaining code
• Programmers spend 90% reading code, 10% writing code

You know you are working on clean code when each routine you read turns out to be pretty much what you expected. - Ward Cunningham (WikiWikiWeb)

• Good code is simple, readable, understandable, maintainable and testable.
• Bad code can be measured by WTFs per minute.

• Write code for the reader, not for the author or the machine
• Principle of Least Astonishment

public class Customer {};
public void AddAccount();

public class Factory {};
public void AddToJobQueue();

public class CustomerFactory {}
public void AddAccountToJobQueue();

// Good - noun or noun phrase
public class Customer
// Bad - fuzzy names
public class EntityProcessor

// Good - verb or verb phrase
public void AddCustomer()
// Bad - fuzzy names
public void Process()

// Short range variables
for (int i = 0; i < 10; i++) {}
// Short method variable names
var balance = GetAccountBalance();
// Longer field variable names
private int _totalAccountBalance;
// Longer global variable names
public int totalBalanceInAllBankAccounts;

// Short public method names
public void GetCustomers();
public void Save();
// Longer private method names
private string ParseHtmlFromFile()
private int GetIdFromAccountHolder()

// Short public class name
public class Account
// Longer private class name
private class AccountNumberGenerator
// Longer derived class name
public abstract class Account
public class SavingsAccount : Account

• Functions should be small -- less than 20 lines
• Minimize the number of parameters
• Avoid flag arguments in favor of two separate methods
• Use smaller named functions, instead of one huge function

• Comments represent a failure
• Old comments are a *lie*
• Explain yourself in code
• Kill commented zombie code
• TODO and summmary Documentation are necessary comments

IDictionary<string, object>

Func<IDictionary<string, object>, Task>

• The internet allows people to communicate with each other.
• The internet of things is about giving things the ability to sense and communicate to other things.

• Smart phones track our steps, our location, light in the room, among other things.
• Activity bands track steps, activity and sleep.
• Nest thermostat recognizes whether you are home or not. Tracks your patterns to save energy.
• Wifi lightbulbs to dim lights and change color based on phone input.
• Whistle is an activity monitor for your dog.

• Arduino
• Netduino
• Raspberry Pi

• Temperature and humidity monitor.
• Light sensor.
• Motion sensor.
• Tweet out information.
• Digital clock or Stopwatch.

public static void Main()
{
    OutputPort led = new OutputPort(Pins.ONBOARD_LED, false);
    while (true)
    {
        led.Write(true);
        Thread.sleep(500);
        led.Write(false);
        Thread.sleep(500);
    }
}