Playing with iterators

iterators.rb

musicians = ["Jimi Hendrix", "Bob Dylan", "Michael Jackson", "Barry White", "Justin Bieber"]

# each: to iterate on elemens
musicians.each do |musician|
  puts "Hello #{musician}"
end

# each_with_index: iterate on element + index
musicians.each_with_index do |musician, index|
  puts "Musician N#{index} - #{musician}"
end

# map: transform an array into a new one
upcased_musicians = musicians.map do |musician|
  musician.upcase
end

first_name_musicians = musicians.map do |musician|
  musician.split.first
end

p first_name_musicians

# count elements verifying a condition
j_count = musicians.count do |musician|
  musician.start_with? "J"
end

p j_count

# select elements verifying a condition
j_musicians = musicians.select do |musician|
  musician.start_with? "J"
end

p j_musicians

# select elements verifying a condition
musicians_with_colleagues = musicians.select do |musician|
  first_letter = musician[0]
  musicians.count {|musician| musician.start_with? first_letter} > 1
end

p musicians_with_colleagues

# # reject elements verifying a condition
non_j_musicians = musicians.reject do |musician|
  musician.start_with? "J"
end

p non_j_musicians