php - 从数据库记录范围中提取高值和低值的算法

Question

我有一个这样的数据结构:

 array (size=10)
   1 => 
    array (size=2)
     'fdate' => string '11/05/12' (length=8)
     'ftime' => string '11:13' (length=5)
   2 => 
    array (size=2)
    'fdate' => string '11/05/12' (length=8)
    'ftime' => string '11:13' (length=5)
   3 => 
    array (size=2)
     'fdate' => string '11/05/12' (length=8)
     'ftime' => string '11:50' (length=5)
  4 => 
    array (size=2)
     'fdate' => string '11/05/12' (length=8)
     'ftime' => string '11:51' (length=5)
  5 => 
    array (size=2)
     'fdate' => string '11/07/12' (length=8)
     'ftime' => string '09:11' (length=5)
  6 => 
    array (size=2)
     'fdate' => string '11/07/12' (length=8)
     'ftime' => string '09:12' (length=5)
  7 => 
    array (size=2)
     'fdate' => string '11/07/12' (length=8)
     'ftime' => string '10:29' (length=5)
  8 => 
    array (size=2)
     'fdate' => string '11/08/12' (length=8)
     'ftime' => string '11:06' (length=5)
  9 => 
    array (size=2)
    'fdate' => string '11/08/12' (length=8)
    'ftime' => string '11:06' (length=5)
  10 => 
    array (size=2)
    'fdate' => string '11/08/12' (length=8)
    'ftime' => string '11:07' (length=5)

在本例中，我需要评估并最终得到每个日期的第一个和最后一个 ftime 值

 fdate     ftime1 ftime2
 11/05/12, 11:13, 11:51
 11/07/12, 09:11, 10:29
 11/08/12, 11:06, 11:07

我有一个这样的循环:

 $struct = array();
 $i = 1;
 foreach($recs as $row){            
   $struct[$i]['fdate'] = $row->fdate;// store fdate
   $struct[$i]['ftime1'] = $row->ftime;// store initial ftime
   $currentfdate = $row->fdate; // use $currentfdate in comparison to $row->fdate

   if($currentfdate <> $row->fdate){
      $struct[$i]['ftime2'] = $row->ftime;// store last ftime
   }

   $i++;
 }

我不确定如何确定 fdate 何时更改以触发 ftime2 的存储。

Answer 1

你可以试试这个:

$temp = array();
foreach($recs as $row){            
   $temp[$row->fdate][]=$row->ftime;
}

foreach($temp as $date=>$value){
  echo $date.'-'.current($value).'-'.end($value);
}