Array Methods Lab

Learning Goals

• Determine if an array contains a particular element using the include? method
• Sort an array using the sort method
• Reverse the contents of an array using the reverse method
• Find the first and last elements in an array using the first and last methods
• Determine the size, or length, of an array using the size method

Instructions

In this lab, we will be coding the solutions for each of the above tasks in the body of a method. In lib/array_methods.rb we've defined a series of methods for you, each of which is responsible for one of the tasks above. Your job is to write the code in the body of each method to get the tests passing.

Each method takes in an argument of an array. You will call the appropriate method, such as include? or first, on that array to get the test passing.

This lab is test-driven so run learn to get started and use the test output to guide you.

Let's do the first one together:

using_include

This method takes in two arguments: an array and an element. The test is expecting the using_include method to return true if the array contains that element and false if it doesn't.

We've already discussed a method that does just that: include?. This method is called on an array and takes in an argument of an element. It returns true if the array contains that element and false if it does not.

Let's get our test passing with the following code:

# lib/array_methods.rb

def using_include(array, element)
  array.include?(element)
end

Run your test suite again, and you should be passing the first one.

using_sort

This method takes in an argument of an array and should return the array, sorted in ascending order. Use the sort method on the array to get this test passing.

using_reverse

This method takes in an argument of an array and should return the array with the contents in reverse order. Use the reverse method on the array to get this test passing.

using_first

This method takes in an argument of an array and should return the first element of that array. Try to get this test passing without using the [] method. Use the first method instead.

using_last

This method takes in an argument of an array and should return the last element of that array. Try to get this test passing without using the [] method. Use the last method instead.

using_size

This method takes in an argument of an array and should return the size, or length, of that array. Use the size method on that array to get this test passing.