how to categorise or group array by date

问题

I have a list of history which is grouped by date DESC like this:

-----------    
28/Feb/2014    
-----------
27/Feb/2014 
-----------   
27/Feb/2014
-----------
27/Feb/2014  
------------    
26/Feb/2014
------------
26/Feb/2014

I want to be printed like this.

-----------    
28/Feb/2014    
-----------
27/Feb/2014    
27/Feb/2014
27/Feb/2014  
------------    
26/Feb/2014
26/Feb/2014

here is my array:

array(
    (int) 0 => array(
        'BriefHistory' => array(
            'id' => '2',
            'created' => '2014-02-28 14:51:08',
            'created_by' => '7827',
            'order_id' => 'OBE10003',
            'brief_instalment_id' => '2',
            'brief_history_type_id' => '1'
        )
    ),
    (int) 1 => array(
        'BriefHistory' => array(
            'id' => '4',
            'created' => '2014-02-27 16:18:40',
            'created_by' => '7827',
            'order_id' => 'OBE10003',
            'brief_instalment_id' => '2',
            'brief_history_type_id' => '4'
        )
    ),
    (int) 2 => array(
        'BriefHistory' => array(
            'id' => '1',
            'created' => '2014-02-27 14:51:08',
            'created_by' => '7827',
            'order_id' => 'OBE10003',
            'brief_instalment_id' => '1',
            'brief_history_type_id' => '1'
        )
    ),
    (int) 3 => array(
        'BriefHistory' => array(
            'id' => '3',
            'created' => '2014-02-26 16:18:09',
            'created_by' => '7827',
            'order_id' => 'OBE10003',
            'brief_instalment_id' => '1',
            'brief_history_type_id' => '3'
        )
    )
)

php:

<?php foreach ($briefHistories as $briefHistorie) { ?>                           
      <div class="brief-summary-row">
           <div>
                <?php echo TimeUtil::format( "d/M/Y", $briefHistorie['BriefHistory']['created']); ?>
           </div>
    </div>
<?php } ?>

回答1:

<?php 
    $current = TimeUtil::format( "d/M/Y", $briefHistories[0]['BriefHistory']['created']); 
    echo '<div class="brief-summary-row"><div>';
    foreach ($briefHistories as $briefHistorie) {      
          $created = TimeUtil::format( "d/M/Y", $briefHistorie['BriefHistory'['created']); 
          echo $created;
          if($created != $current){
                echo '</div></div><div class="brief-summary-row"><div>';
                $current = $created;
          }
     }
     echo '</div></div>';
?>

回答2:

Something along these lines. Could be compacted:

$previous = '';

foreach ($briefHistories as $briefHistorie) {
    $date = TimeUtil::format("d/M/Y", $briefHistorie['BriefHistory']['created']);

    if($date != $previous) {
        echo '<div class="brief-summary-row">';
    }

    echo '<div>'.$date.'</div>';

    if($date != $previous) {
        echo '</div>';
    }
    $previous = $date;
}

回答3:

for others

    $arrayDates = array();
    $i = 0;
    $key = array();
    foreach ($briefHistories as $briefHistorie) {
        $key_name = date('Ymd', strtotime($briefHistorie['BriefHistory']['created']));
        if(!isset($key[$key_name])){
            $key[$key_name]=$i;
            $i++;
        }
        $arrayDates[$key[$key_name]][]= $briefHistorie;
    }



   foreach ($arrayDates as $arrayDate ) {
           echo '<div class="brief-summary-row">';
               foreach ($arrayDate as $data) {
                   echo '<strong>'.date('d-m-Y', strtotime($data['BriefHistory']['created'])).'</strong>';                   
               }           
           echo '</div>';
   }

print out =>

<div class="brief-summary-row">
   <strong>28-02-2014</strong>
</div>
<div class="brief-summary-row">
   <strong>27-02-2014</strong>
   <strong>27-02-2014</strong>
   <strong>27-02-2014</strong>
   <strong>27-02-2014</strong>
</div>
<div class="brief-summary-row">
   <strong>26-02-2014</strong>
   <strong>26-02-2014</strong>
</div>
<div class="brief-summary-row">
   <strong>25-02-2014</strong>
</div>

for other Here is array demo

来源：https://stackoverflow.com/questions/22102004/how-to-categorise-or-group-array-by-date