具有相同键或值的数组不返回

Question

$arrays = array (
    'child1_167'=>'1st', 
    'child1_167'=>'2nd', 
    'child1_165'=>'2nd', 
    'child2_165'=>'1st', 
    'child3_164'=>'2nd', 
    'child1_164'=>'' 
);

$classes = array();
foreach ($arrays as $key=>$value) {

  if($value != '') {
      $exp= explode('_', $key);
      $classes[$exp[0]] = $exp[1];

  }

}
 print_r($classes);

当前它正在返回像这样：

Array ( [child1] => 165 [child2] => 165 [child3] => 164 ) 

但我希望它返回所有键和值，如果value不为空。

我实际上是从表单获取数据。 而我的实际代码是foreach（$ _post as $ key => $ value）

<td>
  <select name="child1_<?php echo child_id(); ?>">
   <option></option>
   <option>1st</option>
   <option>2nd</option>
  </select>
</td>
<td>
  <select name="child2_<?php echo child_id(); ?>">
   <option></option>
   <option>1st</option>
   <option>2nd</option>
  </select>
</td>
<td>
  <select name="child3_<?php echo child_id(); ?>">
   <option></option>
   <option>1st</option>
   <option>2nd</option>
  </select>
</td>

这是表单发布数据。

Array ( [child1_167] => 1st [child2_167] => 2nd [child3_167] => [child1_165] => [child2_165] => 1st [child3_165] => 2nd [child1_164] => 2nd [child2_164] => [child3_164] => 1st ) Array ( [167] => 2nd [165] => 2nd [164] => 1st ) 

Answer 1

问题是，数组的键必须是唯一的，但你设定相同的密钥child1有三个不同的值（ 167 ， 167和165 ），所以你只是每次都覆盖相同的条目。

您可以做的是：

$classes = array();
foreach ($arrays as $key=>$value) {
  if($value != '') {
      $exp= explode('_', $key);
      $classes[$exp[0]][] = $exp[1];

  }
}

这将生成一个多维数组

Answer 2

$arrays = array (
    'child1_167'=>'1st', 
    'child1_167'=>'2nd', 
    'child1_165'=>'2nd', 
    'child2_165'=>'1st', 
    'child3_164'=>'2nd', 
    'child1_164'=>'' 
);

如果在开始时打印$ arrays，则密钥是唯一的，您将找到答案：

echo "<pre>";
print_r($arrays);
echo "</pre>";

Answer 3

以您在注释她中提供的数组为例，该数组具有所有值，并将它们存储为二维关联数组：

 $arrays =  Array ( 
        'child1_167' => '1st' ,
        'child2_167' => '2nd' ,
        'child3_167' => '',
        'child1_165' => '',
        'child2_165' => '1st' ,
        'child3_165' => '2nd' ,
        'child1_164' => '2nd' ,
        'child2_164' => '',
        'child3_164' => '1st' ,
        ) ;


$classes = array();
foreach ($arrays as $key=>$value) {

  if($value != '') {

      $exp= explode('_', $key);
      $child_number=$exp[0];
      $child_id=$exp[1];
      $child_order=$value;
      $classes[$child_number][$child_order] = $exp[1];

  }

}
 print_r($classes);

这是输出：

Array
(
    [child1] => Array
        (
            [1st] => 167
            [2nd] => 164
        )

    [child2] => Array
        (
            [2nd] => 167
            [1st] => 165
        )

    [child3] => Array
        (
            [2nd] => 165
            [1st] => 164
        )

)