day_3_morning.rb

##RECAP
#Arrays ['literal', 'notation', 555]
#While loops
#If statements
#Functions

#The interpreter reads from top down; 
#Compare a sequence of values put them into an array and then can check if it is included in an array; 

##HOMEWORK SUBMISSION
#Add your homework under your student name on your local machine; 
#git add . 
#git commit -m "commit message"
#git push origin master

#create a new pull request with three key points that you want me to look at; 

#To pull down new homework from the repo run git pull upstream master;

##HASH
#A hash is a dictionary; 
#
vices = {}
vices['Groucho'] = 'cigars'
 =>"cigars" 
vices['Chico'] = 'cigars'
 =>"cigars" 
vices['Harpo'] = 'girls'
 =>"girls" 
 
vices = {"Groucho"=>"cigars", "Chico"=>"cigars", "Harpo"=>"girls"} 
#A hash does not have an order; 
#The keys in an array are ordered by index; 

vices.keys
 => ["Groucho", "Chico", "Harpo"] 
vices.values
 => ["cigars", "cigars", "girls"] 
 
#LITERAL HASH
h = {0 => 'Zero', 1 => 'One', :two => 'Two', 'two' => 2} #This is the old hash rocket notation
h = {0: 'Zero', 1: 'One', 2: 'Two', '}

#The key can be anything such as a string, number, symbol; 
#A symbol is most frequently used; 
#Everytime you type in a new string, you put it in a new special string object in memory ("Groucho".object_id)
#Wasting memory by constantly creating the Graucho object; 
#Ruby has invented a symbol, a symbol is like a string, but all identical symbols hold the same place in memory; 

#If you are dealing with simple collections arrays are better, lots of methods such as push and pop; 
#Hashes are better for key value pairs; 

#(users['Jonathan'][:favorite_numbers] + users['Anil'][:favorite_numbers] + users['Erik'][:favorite_numbers]).uniq.sort

##PRY
#'require' pry at the top of your ruby file; 
# Where you want the code to pause in the Ruby environment you can write binding.pry;

##BLOCKS
nums = [1, 2, 3, 5, 7,  11, 13, 17, 19, 23, 39]
i = 0

while i < nums.length
    puts "#{nums[i]}"
    i+=1
end

while x = nums.shift
     puts "#{nums[i]}"
end

#Enumerable means you can do someting to each element in the collection; 
#When you have a collection of things you have access to the method 'magic' method each; 

kittens = "Buttons:Snowball:Fluffy:Minster".split(':')
kittens.each do |kitten|
 puts "The adorable #{kitten}"
end
#kitten within the pipes is an indivudual kitten; 

vices = {
    :groucho => 'cigars',
    :harpo => 'girls',
    :chico => 'pranks'
}

vices.each do |brother, vice| 
 puts "#{brother}, #{vice}"
end

vices.each {|whatsthis| puts "#{whatsthis}"}
12.times do 
    puts "Beetlejuice"
end

12.times do |iteration|
    puts "#{iteration} Beetlejuice!"
end

5.downto(1) do |n| 
    puts "#{n}"
end

10.upto(23) do |n| 
    puts "#{n}"
end

(1..100).each do |num| 
    puts "#{num}"
end

(1..100).to_a

candidates = (1..100).to_a
odds = candidates.select do |i|
    i.odd?
end

smalls = candidates.select do |i|
    i < 23
end

candidates = (1..10)

#Ruby will let you subtract elements from an array; 
(1..10).to_a - [3, 7]
(1..10).to_a - [2, 4, 6 8, 10]
(1..10).to_a + [2, 4, 6, 8, 10]

 => [1, 2, 4, 5, 6, 8, 9, 10]