sort array by a particular value.

[Anon]

Hi,

I looked at all of the stuff in the PHP Manual, but I'm still unsure how to address this problem I have.

I have an array:

$info = array($ip, $mac, $ifDescr, $ifName, $hostname);

All of these variables are related and each instance of the array describes one box. What I want to do, though, is display the information in the array sorted in ascending order by $ifName.

This seems like it should be really easy, but I haven't seen anything addressing this - and I searched the forums. Tough to find a good search term for this, though. Can someone give me a nudge in the right direction? I'm not lazy - I'll read the manual if someone has a relevant link.

Thanks.

[rrijnders]

Well, you first need to understand what kind of structure you are working with.

You say "each instance of the array describes one box". I assmue, then, that you have some other structure (probably an array) holding a whole bunch of "$info" arrays? So you don't have one array, you have an array of arrays; a "two dimensional" array:

array $boxes =>(
  'box1 => array($ip, $mac, $ifDescr, $ifName, $hostname)
  'box2 => array($ip, $mac, $ifDescr, $ifName, $hostname)
  'box3 => array($ip, $mac, $ifDescr, $ifName, $hostname)
)

You want to sort the primary array by some value in the secondary array. Can't do that easily. Just like a DB, you will need to create some type of index keyed by the value you want to sort by. In other words, as you build your $boxes array, you also build a $boxIndex array that can be sorted.

ie: When you:

$info = array($ip, $mac, $ifDescr, $ifName, $hostname);
$boxes["$boxID"]=$info;

...then also:
$boxIndex["$boxID"]=$ifName;

since $ifName is the field you want to sort by. When you are done building the array, you can sort $boxIndex using one of the PHP array functions, then loop through $boxIndex to access $boxes and output in the correct order.

-- HTH
-- Rich