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);

currently it is returning like this:

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

but i want it to return all the keys and value if value is not blank.

I am actually getting the data from form. and my actual code is 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>

and here is the form post data.

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

The problem is that array keys must be unique, but you're setting the same key child1 with three different values ( 167 , 167 and 165 ) so you're just overwriting the same entry each time.

What you could do is:

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

  }
}

which will generate a multi-dimensional array

Answer 2

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

The key are uniques if you print $arrays on the begin you will find the answer:

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

Answer 3

Working with the array you provided in the comments her as an example that has all the values, storing them as a two-dimensional associative array:

 $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);

And this is the output:

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

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

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

)