[Sorting multidimentional arrays?]

My array goes like this:
[code]$array[1][a] = 8253EF
$array[1][b] = joe

$array[2][a] = 2016HG
$array[2][b] = bob

$array[3][a] = 5768NT
$array[3][b] = adam[/code]

I want to sort it so that the item in the [a] key goes ascending alphabetically (alphanumerically), but it stays with its associated name (the b key).

So in the end, I want

[code]$array[1][a] = 2016HG
$array[1][b] = bob

$array[2][a] = 5768NT
$array[2][b] = adam

$array[3][a] = 8253EF
$array[3][b] = joe[/code]

What function is this?

[2 Questions]

1. I have an array, lets say 2,4,6,8
Next, I have a number x (just some random number between 1-10)

Whenever x matches any of the elements of the array, I want it to echo MATCH (for example)

BTW, the variable x changes because it is in a while loop.

[2 Questions]

1. how do I say "if this thing is equal to ANY OF THESE OTHER THINGS"

And these other things are dynamic, and there can be a different quantity of these other things.

2. Can you put a while funtion inside another while function? I tried it and it didn't seem to work... How can it work?

[<textarea> Multi-line input onto a database?]

If I submit a <textarea>'s contents onto a server, the line breaks the user inputs disappear.

Like this forum, I'm hitting enter as I type this post and the line breaks will show when the post is posted.

How would I do this?