Create complex multi-dimensional arrays - I really don't understand the solution

JavaScript
1

This has really confused me. Sometimes JavaScript rips my brain out! :confounded:
As far as I understood a, 5-level array would look like this:

let arr = [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9, "deep"],
[10, 11, 12, "deeper"],
[13, 14, 15, "deepest"]
];

So why does the solution resemble this structure?

let arr = [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9, ["deep"]],
[10, 11, 12, [["deeper"]]],
[13, 14, 15, [[["deepest"]]]
];

The instructions are not to add more levels to each existing level, just to include the strings, and I’m not sure what the purpose of [[ ]] and [[[ ]]] are in the last two levels.

https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/basic-data-structures/create-complex-multi-dimensional-arrays

2

this is a two levels array, you have 5 monodimensional arrays inside the outer array
you can reach all the things inside with only two brackets: arr[3][3] is "deeper"

in the other case if you wanted to get "deeper" you would need more. You get "deeper" with arr[3][3][0][0]

here visual rapresentation of the two arrays: (there was a closing square bracket in the second case that I had to add to get this)

image
image1187×433 40.9 KB

[Obteined using JavaScript Tutor]

2 Likes
3

Thank you so much. I totally misunderstood levels. :man_facepalming:
I’ll explore that JavaScript Tutor.
I solved the challenge in a different way from the solution.

4

the solution provided is just a way, there is not a definite way to solve this challenge as it says you can add the elements where you want, they just need to be at the indicated level of depth

5

I’m just glad to get though it.
Thanks again.

6

JS has new functions for nested arrays, flat and flatMap. You can check them in official documentation.


7

Wonderful, thank you. :slight_smile: