# Flatten Array

Take a nested list and return a single flattened list with all values except nil/null.

The challenge is to write a function that accepts an arbitrarily-deep nested list-like structure and returns a flattened structure without any nil/null values.

For Example

input: [1,[2,3,null,4],[null],5]

output: [1,2,3,4,5]

## Setup

There are two different methods of getting set up to run the tests with Objective-C:

- Create an Xcode project with a test target which will run the tests.
- Use the ruby gem `objc` as a test runner utility.

Both are described in more detail here: http://exercism.io/languages/objective-c

### Submitting Exercises

When submitting an exercise, make sure your solution file is in the same directory as the test code.

The submit command will look something like:

```shell
exercism submit <path-to-exercism-workspace>/objective-c/flatten-array/FlattenArray.m
```

You can find the Exercism workspace by running `exercism debug` and looking for the line beginning
with Workspace.

## Source

Interview Question [https://reference.wolfram.com/language/ref/Flatten.html](https://reference.wolfram.com/language/ref/Flatten.html)

## Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.