在多维数组中查找索引

Question

Basically I have this array:

array(
  [0] => array("id" => "0", "header" => "img1"),
  [1] => array("id" => "4", "header" => "img4")
  [2] => array("id" => "6", "header" => "img6")
)

If I have $id = "4", how can I extract the index [1] to obtain "header" value?

Answer 1

You will want to do a foreach loop for this. But honestly if you structured your array indexes better than you could just to a simple isset test and then grab the value once you verify it is there.

The right way:

$headers = array(0 => 'img1', 4 => 'img4', 6 => 'img6');

if (isset($headers[$index])) {
  return $headers[$index];
}

Here is how to deal with it with your array (much more costly from a processing standpoint):

$headers = array(
  0 => array("id" => "0", "header" => "img1"),
  1 => array("id" => "4", "header" => "img4"),
  2 => array("id" => "6", "header" => "img6")
);

foreach ($headers AS $value) {
  if ($value['id'] == $index) {
    return $value['header'];
  }
}