blocks.rb

# ONE LINE SYNTAX
 { |i| i * 2}

# MULTI-LINE SYNTAX
do |i|
  i * 2
end




# USE OF BLOCK WITHOUT PARAMETERS
def timer
  start_time = Time.now

  yield # EXECUTE THE BLOCK

  end_time = Time.now
  puts "Elpased time = #{end_time - start_time}"
end

timer do
  puts "starting task 1"
  sleep(2)
  puts "Task 1 is done"
end

timer do
  puts "starting task 2"
  sleep(1)
  puts "Task 2 is done"
end



# BLOCK CAN TAKE PARAMETERS
def greet(name, last_name)
  puts yield(name, last_name)
end

greet("john", "doe") do |elephant, elephant_last_name|
  "Greetings #{elephant.capitalize} #{elephant_last_name.capitalize}, you look confused today"
end

greet("john") do |name|
  "Bonjour #{name}, tu as l'air confus"
end

iterators.rb

musicians = ["David Gilmour", "Roger Waters", "Richard Wright", "Nick Mason"]

# EACH OPERATOR
musicians.each do |musician|
  puts "Hello #{musician}"
end


musicians.each { |musician| puts "Hello #{musician}" }

# EACH_WITH_INDEX
musicians.each_with_index do |musician, index|
  puts "#{index + 1} - #{musician.downcase}"
end

# MAP
upcase_musicians = musicians.map.object_id do |musician|
  musician.upcase
end

# COUNT
count_musician = musicians.count do |musician|
  musician
end

# SELECT
select_musicians = musicians.select do |musician|
  musician.start_with?("R")
end

# MANY MORE
# http://ruby-doc.org/core-2.5.0/Array.html
# http://ruby-doc.org/core-2.5.0/Enumerable.html

musicians.rb

musicians = ["Jimmy Page", "Robert Plant", "John Paul Jones", "John Bonham"] # create array of musicians


musicians.size == musicians.length # return number of element in array

musicians << "ben" # add element to array

musicians[0] == musicians.first # return first element
musicians.last == musicians[-1] # return last element

musicians[1] = "new value" # re-assign the element at index 1


musicians.delete("new value") # /!\  WILL DELETE ALL ELEMENT THAT MATCH /!\
musicians.delete_at(1) # remove element at index 1
musicians.shift # remove first element
musicians.pop # remove last element


# LOOP OVER ELEMENTS
for musician in musicians
  puts musician
end

# LOOP OVER INDEXES
for index in 0...musicians.length
  musician = musicians[index]
  puts "#{index + 1} - #{musician}"
end