Intro To Ruby

What is Ruby?

Techotopia

Ruby is an object-oriented interpreted scripting language. When we say it is interpreted we mean to say that the Ruby source code is compiled by an interpreter at the point of execution (similar in this regard to JavaScript and PHP). This contrasts with compiled languages such as Java, Objective C, C, or C++ where the code is pre-compiled into a binary format targeted to run on a specific brand of microprocessor.

History of Ruby

Techotopia

Ruby was created by Yukihiro Matsumoto (more affectionately known as Matz) in Japan starting in 1993. Matz essentially kept Ruby to himself until 1995 when he released it to the public. Ruby quickly gained a following in Matz's home country of Japan in the following years, and finally gained recognition in the rest of the programming world beginning in the year 2000. From that point on Ruby has grown in popularity, particularly because of the popularity of the Ruby on Rails web application development framework.

How to Try Ruby Out

Every Mac comes with Ruby inside!

$ irb

irb(main):001:0> 2 + 2
=> 4
irb(main):002:0>

Comparing to JavaScript

Basic Differences

Define a Method/Function with a Parameter/Argument

JavaScript

var say = function(something) {
  console.log(something);
};

say("hello");

Ruby

def say(something)
  puts something
end

say('hello')
say 'gello'

Define For Loop

JavaScript

var names = ["Sonja", "Alex", "Jared"]

for (i = 0; i < names.length; i++) {
  console.log(names[i]);
}

Ruby

@names = ["Sonja", "Alex", "Jared"]

names.each do |n|
  p n
end

Define a Map Function

JavaScript

var names = ["Sonja", "Alex", "Jared"]

var nameLengths = _.map(names, function(el) {
  el.length
})

Ruby

names = ["Sonja", "Alex", "Jared"]

name_lengths = names.map do |n|
  n.count
end

# OR

name_lengths = names.map { |n| n.count }

Ruby has awesome stuff that JS doesn't

For example: any? and present? and blank? that return true or false.

def greet(friends)
  friends.each do |f|
    p "Hello #{f}"
  end
end

my_friends = ["Andrew", "Bill", "Sally"]

if my_friends.any? # checks if there are any values in an array
  have_a_party(my_friends)
end

Ruby also has awesome iterators built right in (a la UnderscoreJS)

For example: each and map and inject and those even have some fancy syntax you can use.

people = [{ name: "Mary", age: 34 },
          { name: "Sonja", age: 54 },
          { name: "John", age: 64 }]

people.each do |person|
  puts "person[:name] is #{person[:age]} years old."
end
#=> "Mary is 34 years old"
#=> "Sonja is 54 years old"
#=> "John is 64 years old"

people.map(&:age) #=> [34, 54, 64]
people.inject(0) { |sum, n| sum + n[:age] } #=> 152

How to run a ruby script inside a file

1. $ touch script.rb
2. $ sublime script.rb
3. $ ruby script.rb
4. THAT'S IT!
5. From irb you can run a ruby file by loading it $ load './filename.rb'

Ruby Tutorial: Try Ruby