Ruby algorithm solving

Question

So I have a basic problem that needs to be solved. I need to take the following nested array [1, 2, ["str", 1], [[2]]] and return [1,2,"str",1,2]. Ultimately removing all nested arrays. The following is my incomplete solution:

test = [1, 2, ["str", 1], [[2]]]

def remove_array(array)
    new_array = []
    array.each do |item|
        if item != Array
            puts "you are here"
            new_array << item
        else
            remove_array(item)
        end
    end
end

remove_array(test)

This is a classic recursion method. However, I cant seem to think of how to maintain new_array. Every time I pass the item that is an array to it, new_array doesn't maintain its state. I would also like to point out that I am aware of the built in method flatten as I am trying to solve the solution without said method. Any advice would be greatly appreciated.

Answer 1

def my_flatten(arr)
  result = []

  arr.each do |el|
    if el.is_a?(Array)
      result.concat(my_flatten(el))
    else
      result << el
    end
  end

  result
end

You generally had the right idea, but you were never adding the inner array elements into your result.

Answer 2

def remove_array(array)
  new_array = []
  array.each do |e|
    if e.is_a?(Array)
      new_array += remove_array(e)
    else
      new_array << e
    end
  end
  new_array
end

Answer 3

You can call flatten on you array.

a = [1, 2, ["str", 1], [[2]]]
=> [1, 2, ["str", 1], [[2]]]
   a.flatten
=> [1, 2, "str", 1, 2]

Answer 4

In Ruby, there is a convenient built-in method called flatten

It will "flatten" your array so that all the inside arrays disappear, and it returns one array with all elements inside

Edit:

Sorry editing this. Forgot that you were using recursion for your solution. Since you're essentially creating a new array each recursion, I'm not exactly sure how I would fix your solution at this moment.

Answer 5

just use the flatten! :) keep it simple..

test = [1, 2, ["str", 1], [[2]]]

def remove_array(array)
   array.flatten!
   return array
end

remove_array(test)

2.2.1 :024 >   remove_array(test)
=> [1, 2, "str", 1, 2]

I hope this helps everybody! Thanks