Mastering Ruby Closures

Test Your Understanding!

Time to put on that thinking cap and flex that gray matter. Remember, in order to really understand the material, you should attempt to complete the following exercises. None of them should take too long, and you have my permission to peek at the solutions if you get stuck.

1. Implement Array#map using Array#each:

   %w(look ma no for loops).map do |x|
     x.upcase
   end

   This should return ["LOOK", "MA", "NO", "FOR", "LOOPS"].

2. Implement String#each_word:

   "Nothing lasts forever but cold November Rain".each_word do |x|
     puts x
   end

   This should output:

   Nothing
   lasts
   forever
   but
   cold
   November
   Rain

3. It’s your turn to implement File.open. Start off with the Ruby documentation. The key here is to understand ...