Become familiar with using common iterators introduced in the previous lesson.
???
?: Using .each
Let's try out the enumerator methods we just learned. Refer back to the previous lesson to help you pass this challenge. Below, we have a variable, lunch_menu, set equal to an array of lunch menu items.
Since you're super hungry and super excited about lunch, use the .each method to enumerate over the array and append an "!" ("exclamation mark") to each menu item. You can use the << ("shovel operator") on each menu item string to add an "!" like this: "pizza" << "!".
lunch_menu = ["pizza", "sandwich", "sushi", "soup", "salad"]Which piece of code will achieve the desired result?
( )
lunch_menu << "!"(x)
lunch_menu.each do |lunch_item|
lunch_item << "!"
end( )
lunch_menu.each do |lunch_item|
"#{lunch_item}!"
end( )
lunch_menu.each do |lunch_item|?: Using .collect
Below we have a variable, nums, set equal to an array of numbers. Enumerate over the array with the .collect method and return a new array of the squares of those numbers.
nums = [1, 2, 3, 4]Which piece of code will achieve the desired result?
(x)
nums.collect { |n| n * n }( )
nums.collect do |n|
n + n
end( )
nums.collect { |n| nn }( )
nums.collect do |n|
n
end?: Using .select
Below we have a variable, odds_and_evens, set equal to an array of numbers. Use the .select enumerator to iterate over the array and return any even numbers. This requires checking if a number is even. If you're unsure how to do that, reference the Ruby Documentation or try a google search!
odds_and_evens = [1, 3, 2, 18, 5, 10, 24]Which piece of code will achieve the desired result?
( )
odds_and_evens.select do |n|
n / 2
end( )
odds_and_evens.select do |n|
n % 2
end(x)
odds_and_evens.select do |n|
n.even?
end( )
odds_and_evens.select do |n|
n + 2
end?: Using .find
Below we once again have a variable, odds_and_evens, set equal to an array of numbers. This time, use the .find method to iterate over the array and return only the first array element that is odd.
odds_and_evens = [2, 3, 2, 18, 5, 10, 24]Which piece of code will achieve the desired result?
( )
odds_and_evens.find do |num|
num.even?
end( )
odds_and_evens.find do |num|
num / 2
end( )
odds_and_evens.find do |num|
num
end(x)
odds_and_evens.find do |num|
num.odd?
end?: Using delete_if
Below we have a variable, cats_and_dogs, set equal to an array of strings that are either a "cat" or a "dog". We all know that cats and dogs don't get along. Iterate over the array and delete the elements that represent dogs.
cats_and_dogs = ["cat", "cat", "dog", "cat", "dog", "dog"]Which piece of code will achieve the desired result?
(x)
cats_and_dogs.delete_if do |pet|
pet == "dog"
end( )
cats_and_dogs.delete_if do |pet|
pet == "cat"
end( )
cats_and_dogs.delete_if do |pet|
pet == pet
end( )
cats_and_dogs.delete_if do |pet|
"dog"
end?: Using include?
Below we have a variable, famous_cats, set equal to an array of famous cats. Use the .include? method to check and see if the array includes the string "Maru".
famous_cats = ["Maru", "Lil Bub", "Grumpy Cat"]Which piece of code will achieve the desired result?
(x)
famous_cats.include?("Maru")( )
famous_cats.include?( )
famous_cats.include?(true)?: Using any?
Below we have a variable, quiet_and_loud, that is set equal to an array of strings. Use the .any? method to iterate over the array to determine if any of the words contained there are loud (upcased).
quiet_and_loud = ["hi", "HI", "shhh", "WHAT?!"]Which piece of code will achieve the desired result?
( )
quiet_and_loud.any? { |w| w.upcase }( )
quiet_and_loud.any? { |w| w.upcase? }(x)
quiet_and_loud.any? do |word|
word == word.upcase
end( )
quiet_and_loud.any? do |w|
w
end???
View Enumerator Coding Challenge on Learn.co and start learning to code for free.