Util to Flatten an array of arbitrarily nested arrays of integers into a flat array of integers. e.g. [[1,2,[3]],4] -> [1,2,3,4]

README.md

ArrayUtil

I wrote a class with a custom :flatten method in Ruby similar to [1,2,3].flatten This method recursively flatten an Array

Prerequisite

You'll need:

• ruby
• minitest

The test was written using Minitest. You can install minitest in the command line by typing:

$ gem instal minitest

Usage

You can try the method directly in the ruby console

Start irb

$ irb

Require ArrayUtil

> require './array_util.rb'

Pass the array as an argument of ArrayUtil flatten method

> ArrayUtil.flatten([1,2,3])

Test

To run the test in the command line type:

$ ruby array_util_test

array_util.rb

# Flatten an array recursively
class ArrayUtil
  def self.flatten(array)
    flatten_array = []
    array.each do |item|
      if item.is_a? Array
        flatten_array.concat(flatten(item))
      else
        flatten_array << item
      end
    end
    flatten_array
  end
end

array_util_test.rb

#! /usr/bin/env ruby
require 'minitest/autorun'
require_relative 'array_util.rb'

# Test ArrayUtil
class ArrayUtilTest < Minitest::Test
  def test_flatten
    assert_equal [1, 2, 3, 4, 5, 6, 7],
                 ArrayUtil.flatten([1, 2, [3, 4, [5, 6]], 7])
  end
end