PHP: Building an array of dates with two types of sorting -

i have array of appointments need order in special way. let's current date 30 may 2016 , current time 11:00h:

$currenttimestamp = strtotime("05/30/2016 11:00"); // results in 1464620400 

first, here comes array of appointments contains timestamps end of each appointment:

$alldates = [ '2016-05-24' => [     [         'end' => 1464086700      ] ], '2016-05-27' => [     [         'end' => 1464349500     ] ], '2016-05-30' => [     [         'end' => 1464606900      ],     [         'end' => 1464614100     ],     [         'end' => 1464623100     ] ], '2016-05-31' => [     [         'ende' => 1464705900     ] ] 

];

here come requirements resorting array:

• all appointments end later current timestamp must ordered descending.
• all appointments end earlier current timestamp must ordered ascending.

my desired output following:

$desiredfinalarrdates = [ '2016-05-31' => [     [         'end' => 1464705900     ] ], '2016-05-30' => [     [         'end' => 1464623100     ] ], // !!! past dates start here, ascending...  '2016-05-24' => [     [         'end' => 1464086700      ] ], '2016-05-27' => [     [         'end' => 1464349500     ] ],  '2016-05-30' => [     [                   'end' => 1464606900     ],     [         'end' => 1464614100     ]  ]  ]; 

how achieve desired ordering of $alldates array?

-------------- attempt far ----------------

$future = []; $past = [];  foreach ($alldates $key => $subarr) {     foreach ($subarr $value) {         if ($value['end'] >= $currenttimestamp) {             $future[$key][] = $value;         } else {             $past[$key][] = $value;         }     } }  asort($past);  $desiredfinalarrdates  = array_merge($future, $past); 

the problem array_merge keys overwritten.

if performance doesn't matter, can this.

1. create 2 arrays $arrbefore , $arrafter.  2. iterate $alldates array (and sub-arrays) , compare current value $currenttimestamp.  3. if lower add $arrbefore array, else $arrafter.  4. sort arrays correspondigly (descending/ascending).  5. finally, merge 2 arrays. 

edit: create 2 arrays $arrbefore , $arrafter sorted correctly. achieve desired output, not possible in form. that's because can't have same key multiple times in array (i.e. 2016-05-30 in case).

<?php   $currenttimestamp = strtotime("05/30/2016 11:00");  $alldates = [ '2016-05-24' => [     [         'end' => 1464086700      ] ], '2016-05-27' => [     [         'end' => 1464349500     ] ], '2016-05-30' => [     [         'end' => 1464606900      ],     [         'end' => 1464614100     ],     [         'end' => 1464623100     ] ], '2016-05-31' => [     [         'end' => 1464705900     ] ]     ];  $arrbefore = array(); $arrafter = array();  foreach($alldates $currkey => $currdatearr){     foreach($currdatearr  $currdate){          if($currdate['end'] < $currenttimestamp){             if(array_key_exists($currkey,$arrbefore)){                 $arrbefore[$currkey][] = $currdate['end'];                       }else{                 $arrbefore[$currkey] = array($currdate['end']);             }         }else{             if(array_key_exists($currkey,$arrafter)){                 $arrafter[$currkey][] = $currdate['end'];                        }else{                 $arrafter[$currkey] = array($currdate['end']);             }         }     } }  //sort arrays ksort($arrbefore); krsort($arrafter);  //sort sub-arrays foreach($arrbefore $subarr){ asort($subarr);  } //sort sub-arrays foreach($arrafter $subarr){ rsort($subarr);  }  print_r($arrbefore);  print_r($arrafter); 

prints:

array ( [2016-05-24] => array ( [0] => 1464086700 ) [2016-05-27] => array ( [0] => 1464349500 ) [2016-05-30] => array ( [0] => 1464606900 [1] => 1464614100 ) )  array ( [2016-05-31] => array ( [0] => 1464705900 ) [2016-05-30] => array ( [0] => 1464623100 ) )   ?>