You can use function inArray below, to search:
- multidimensional arrays
- for substrings (case [in]sensitive)
- for sub-arrays
- get array of keys of found values
<?php
/** Function 'inArray' checks if a value exists in an array (also multidimensional): if string as substring (case-[in]sensitive), or other value as a element of the same type
*
* @param mixed $needle Value to find (string: as (sub)string, array: as (sub)array, other: as exact element)
* @param array $haystack The array for search (can be multidimensional)
* @param bool $also_similar (optional, default: false)
*  for string $needle - default: false, means case-sensitive,
*              1: case-insensitivity comparision
*              2: case-insensitivity comparision, and also any element of $haystack can be substring of $needle
*  for array $needle - default: $needle has to be exact element of $haystack
*              1: array $needle also can have the same values as values of any $haystack element (regardless of order and keys!)
*              2: array $needle values also can be sub-array of any element of $haystack (multidimensional)
*  for others - doesn't matter
* @param bool $return_keys (optional, default: false) If true, returns array of keys of found values
* @return bool Whether $needle is found in the array, or keys for found values (first dimension only)
*/



function inArray($needle, $haystack, $also_similar = false, $return_keys = false) {

  if (!is_array($haystack)) return false;
  if ($needle===$haystack) return true;
  if ($also_similar!==false) if ($also_similar<3) {
    if (is_array($needle)) {

      if (in_array($n=$needle, $h=$haystack, true)) {if ($return_keys) $res[]=$key; else return true;}
      elseif ($also_similar>0) {
        sort($n);
        sort($h);
        if (($n===$h) || (in_array($n, $h, true))) {if ($return_keys) $res[]=$key; else return true;}
        elseif ($also_similar>1) {
          $h = array_intersect($h, $n);
          sort($h);
          if ($n===$h) {if ($return_keys) $res[]=$key; else return true;}
        }
      }
    }
  } else $also_similar-=10;

  foreach ($haystack as $key => $value) {
    if ($needle===$value) {if ($return_keys) $res[]=$key; else return true;}
    elseif ((is_string($needle)) && (is_string($value))) {
      if (
        (strpos($value, $needle)!==false)
        || ($also_similar==1) && (stripos($value, $needle)!==false)
        || ($also_similar==2) && (stripos($needle, $value)!==false)
      ) {
        if ($return_keys) $res[]=$key; else return true;
      }
    } elseif (is_array($value)) {
      if(is_array($needle)) {
        if (in_array($needle, $value, true)) {if ($return_keys) $res[]=$key; else return true;}
        elseif ($also_similar>0) {
          $n = $needle;
          sort($n);
          $h = $value;
          sort($h);
          if (($n===$h) || (in_array($n, $h, true))) {if ($return_keys) $res[]=$key; else return true;}
          elseif ($also_similar>1) {
            $h = array_intersect($h, $n);
            sort($h);
            if ($n===$h) {if ($return_keys) $res[]=$key; else return true;}
          }
        }
      }
      if (inArray($needle, $value, $also_similar+10, $return_keys)) {if ($return_keys) $res[]=$key; else return true;}
    }
  }

  if (($return_keys)&&(is_array($res))) return $res;  else return false;

}

// Examples


$a=array (
  1 => 'zero',
  0 => 'zero1',
  2 =>
  array (
    'X' => 'AAZery',
    'Y' => 'Zero',
    'Z' => 1234,
    0 =>
    array (
      1 => 12345,
      2 => 'ZEro2',
      5 => 'Hello',
    ),
  ),
  'end' => '123',
)

var_dump(inArray(123,$a));  //bool(false)
var_dump(inArray(1234,$a));  //bool(true)
var_export(inArray(1234,$a,0,TRUE));  //array (  0 => 2, )

var_dump(inArray("1234",$a));  //bool(false)
var_dump(inArray("23",$a));  //bool(true)
var_export(inArray("23",$a,0,TRUE));  //array (   0 => 'end', )

var_dump(inArray(12345,$a));  //bool(true)

var_dump(inArray("zer",$a));  //bool(true)
var_export(inArray("zer",$a,0,TRUE));  /* array (
  0 => 1,
  1 => 0,
) */

var_dump(inArray("Zer",$a));  //bool(true)
var_dump(inArray("ZER",$a));  //bool(false)

var_dump(inArray("ZER",$a,1));  //bool(true)
var_export(inArray("ZER",$a,1,TRUE)); /* array (
  0 => 1,
  1 => 0,
  2 => 2,
) */

var_dump(inArray("ZERo2",$a,1));  //bool(true)
var_dump(inArray("ZERo2",$a));  //bool(false)

var_dump(inArray(array(1=>12345,2=>"ZEro2"),$a));  //bool(false)
var_dump(inArray(array(2=>"ZEro2",1=>12345,"Hello"),$a));  //bool(false)

var_dump(inArray(array(2=>"ZEro2",1=>12345,"Hello"),$a,1));  //bool(true)
var_export(inArray(array(2=>"ZEro2",1=>12345,"Hello"),$a,1,TRUE));  //array (  0 => 2,)

var_dump(inArray(array(2=>"ZEro2",1=>12345),$a,2));  //bool(true)
var_export(inArray(array(2=>"ZEro2",1=>12345),$a,2,TRUE));  //array (  0 => 2,)

var_dump(inArray(array(2=>"ZEro2",1=>12345,"Hello"),$a,3));  //bool(false)


?>