Ruby Array Map and Each

map_each_array.rb

# .each is pretty easily, and simply loops through the array. 

colors = ["red", "green", "blue"]

colors.each do |color|
  puts color
end

# What is the "return value" of each? 

mystery_colors = colors.each do |color|
  puts color
end

# The mystery colors here are the original colors!!!
puts mystery_colors
# => ["red", "green", "blue"]

# the return value of .each is the original array!

# It would appear at first that .map does the same thing

colors.map do |color|
  puts color
end

# But what is the return value of .map? 

mystery_colors = colors.map do |color|
  puts color
end

# But its all blank!
puts mystery_colors
# => [nil, nil, nil]

# Map returns a new array! The contents of each element are from the "return" of each do/end block iteration.
# (puts returns nil)

# This is useful for creating modified arrays

mystery_colors = colors.map do |color|
  color.upcase
end

# Now you have upcased colors!
puts mystery_colors