Array Sorting

Hi All, I've got an array which has the following properties: $file_array[$filename] = array ("Date" => $Date, "size" => $size, "permissions" => $permissions); I can quite happily sort the array by filename (using natksort and natkrsort), which I found on the php manual - and for reference have included as a PS!!!! What I'm not sure about doing is sorting by say Size or Date? I've again had a look through the php manual but I'm not sure how to sort by a property... Can anyone point me in a direction? Cheers Nunners PS.... as promised! function natksort(&$aToBeSorted) { $aResult = array(); $aKeys = array_keys($aToBeSorted); natcasesort($aKeys); foreach ($aKeys as $sKey) { $aResult[$sKey] = $aToBeSorted[$sKey]; } $aToBeSorted = $aResult; return True; } function natkrsort(&$aToBeSorted) { $aResult = array(); $aKeys = array_keys($aToBeSorted); $aKeys = array_reverse(natcasesort($aKeys)); foreach ($aKeys as $sKey) { $aResult[$sKey] = $aToBeSorted[$sKey]; } $aToBeSorted = $aResult; return True; }