Convert a string of numbers to get a value from a multidimensional array

Question

I need to convert a string, such as 010 to get the value from that incremented index. The array could look something like the following:

$data[0] = [
    '0 Depth'
];
$data[0][1] = [
    '01 Depth'
];
$data[0][1][0] = [
    '010 Depth'
];

The function will need to essentially grab the string inside $data[0][1][0]. I've taken a look at array_reduce, but I don't think it's what I'm looking for.

What's the most fundamental way to do this?

Thanks!