21.even?

1.next.next

1.methods.sort

['rock','paper','scissors'].index('rock')

3.between?(2,4)

words = ["foo", "bar", "baz"]
words[1]

words = ["foo", "bar", "baz"]
words.[](1)

"Ruby".length

# String Interploation
def string_length_interpolater(incoming_string)
  "The string you just gave me has a length of #{incoming_string.length}"
end

# Search in a String
"[Luke:] I can’t believe it. [Yoda:] That is why you fail.".include? 'Yoda'

"Ruby is a beautiful language".start_with? "Ruby"

"I can't work with any other language but Ruby".end_with? 'Ruby'

"I am a Rubyist".index 'R'

puts 'i am in lowercase'.upcase #=> 'I AM IN LOWERCASE'

'This is Mixed CASE'.downcase

"ThiS iS A vErY ComPlEx SenTeNcE".swapcase

'Fear is the path to the dark side'.split(' ')
# ["Fear", "is", "the", "path", "to", "the", "dark", "side"]

# concatenating strings
'Ruby' + 'Monk'

"Ruby"<<"Monk"

# Replacing the first substring 
"I should look into your problem when I get time".sub('I','We')


# gsub has a global scope
"I should look into your problem when I get time".gsub('I','We')

#  replaces all the vowels with the number 1
'RubyMonk'.gsub(/[aeiou]/,'1')

# replace all the characters in capital case with number '0' 
'RubyMonk Is Pretty Brilliant'.gsub(/[A-Z]/,'0')

'RubyMonk Is Pretty Brilliant'.match(/ ./)
# I. regex search a space and any character, '.'

'RubyMonk Is Pretty Brilliant'.match(/ ./, 9)
# P

def sort_string(string)
  string.split(" ").sort{|x, y| x.length <=> y.length}.join(" ")
end

def find_frequency(sentence, word)
  sentence.downcase.split.count(word.downcase)
end

# loop and break if
loop do
  monk.meditate
  break if monk.nirvana?
end

# times
def ring(bell, n)
  n.times do
    bell.ring
  end
end

# empty ruby
[]

Array.new

[1,2,3,4,5]
# is the same as
(1..5).to_a 

[1, 2, 3, 4, 5][2] # 3

[1, 2, 3, 4, 5][-5] # 1
[1, 2, 3, 4, 5][-2] # 4


[1, 2, 3, 4, 5]<<"woot"
# is the same as 
[1, 2, 3, 4, 5].push("woot")
# is the same as 
[1, 2, 3, 4, 5].push("woot")

[1, 2, 3, 4, 5].map { |i| i + 1 }
# => [2, 3, 4, 5, 6]

[1,2,3,4,5].map { |i| i * 3 }
[3, 6, 9, 12, 15]

# filtering with select
# select even numbers
[1,2,3,4,5,6].select {|number| number % 2 == 0}

# => [2, 4, 6]

names = ['rock', 'paper', 'scissors', 'lizard', 'spock']
names.select {|word| word.length > 5}
# => ["scissors", "lizard"]

# delete element 5
[1,3,5,4,6,7].delete(5)

# delete_if
[1,2,3,4,5,6,7].delete_if{|i| i < 4 }

# delete all even numbers
[1,2,3,4,5,6,7,8,9].delete_if{ |i| i % 2 == 0}

# length and size are the same
[ 1, 2, 3, 4, 5 ].length   #=> 5

array = [1, 2, 3, 4, 5]
for i in array
  puts i
end

# Copy the values less than 4 in the array stored in the source variable into the array in the destination variable
def array_copy(source)
  destination = []
  for number in source
    # Add number to destination if number
    # is less than 4
    destination << number if number < 4
  end
  return destination
end

# prints all the values in an array
array = [1, 2, 3, 4, 5]
array.each do |i|
  puts i
end

# using each in stead of for
def array_copy(source)
  destination = []
  source.each do |number|
    # Add number to destination if number
    # is less than 4
    destination << number if number < 4
  end
  return destination
end

def number_shuffle(number)
  no_of_combinations = number.to_s.size == 3 ? 6 : 24
  digits = number.to_s.split(//) #  '' is an empty String, whereas // is an empty Regexp:
  combinations = []
  combinations << digits.shuffle.join.to_i while combinations.uniq.size!=no_of_combinations
  combinations.uniq.sort
end

options = { :font_size => 10, :font_family => "Arial" }

options = { font_size: 10, font_family: "Arial" }

grades = Hash.new
grades["Dorothy Doe"] = 9

restaurant_menu = {
  "Ramen" => 3,
  "Dal Makhani" => 4,
  "Tea" => 2
  }
  
restaurant_menu["Ramen"] #=> 3

restaurant_menu = {}
# set the values for each item separately here:
restaurant_menu["Dal Makhani"] =4.5
restaurant_menu["Tea"] =  2

# default value
grades = Hash.new(0)

# Or by using the default= method:
grades = {"Timmy Doe" => 8}
grades.default = 0

# Accessing a value in a Hash requires using its key:
puts grades["Jane Doe"] # => 10

# each in a hash
restaurant_menu = { "Ramen" => 3, "Dal Makhani" => 4, "Coffee" => 2 }
restaurant_menu.each do | item, price |
  puts "#{item}: $#{price}"
end

# the above is the same as the following
restaurant_menu = { "Ramen" => 3, "Dal Makhani" => 4, "Coffee" => 2 }
restaurant_menu.each { |item, price| puts "#{item}: $#{price}"}

# Increase the price of all the items in the restaurant_menu by 10%.
restaurant_menu = { "Ramen" => 3, "Dal Makhani" => 4, "Coffee" => 2 }
restaurant_menu.each do |item, price|
  restaurant_menu[item] = price + (price * 0.1)
end



# keys
restaurant_menu = { "Ramen" => 3, "Dal Makhani" => 4, "Coffee" => 2 }
restaurant_menu.keys

# Creating hash in different ways
normal = Hash.new
was_not_there = normal[:zig]
puts "Wasn't there:"
p was_not_there

# create a default value
usually_brown = Hash.new("brown")
pretending_to_be_there = usually_brown[:zig] # :zig can be anything
puts "Pretending to be there:"
p pretending_to_be_there

#=> Wasn't there:
#=> nil
#=> Pretending to be there:
#=> "brown"

chuck_norris = Hash[:punch, 99, :kick, 98, :stops_bullets_with_hands, true]
p chuck_norris

#=> {:punch=>99, :kick=>98, :stops_bullets_with_hands=>true}

def artax
  a = [:punch, 0]
  b = [:kick, 72]
  c = [:stops_bullets_with_hands, false]
  key_value_pairs = [a, b, c]
  Hash[key_value_pairs]
end
p artax

#=> {:punch=>0, :kick=>72, :stops_bullets_with_hands=>false}

>> p :name             # Same as 'puts :name.inspect'
:name