in_array() and multidimensional array

Question

I use in_array() to check whether a value exists in an array like below,

$a = array("Mac", "NT", "Irix", "Linux");
if (in_array("Irix", $a)) 
{
    echo "Got Irix";
}

//print_r($a);

but what about an multidimensional array (below) - how can I check that value whether it exists in the multi-array?

$b = array(array("Mac", "NT"), array("Irix", "Linux"));

print_r($b);

or I shouldn't be using in_array() when comes to the multidimensional array?

Answer 1

in_array() does not work on multidimensional arrays. You could write a recursive function to do that for you:

function in_array_r($needle, $haystack, $strict = false) {
    foreach ($haystack as $item) {
        if (($strict ? $item === $needle : $item == $needle) || (is_array($item) && in_array_r($needle, $item, $strict))) {
            return true;
        }
    }

    return false;
}

Usage:

$b = array(array("Mac", "NT"), array("Irix", "Linux"));
echo in_array_r("Irix", $b) ? 'found' : 'not found';

Answer 2

If you know which column to search against, you can use array_search() and array_column():

$userdb = Array
(
    (0) => Array
        (
            ('uid') => '100',
            ('name') => 'Sandra Shush',
            ('url') => 'urlof100'
        ),

    (1) => Array
        (
            ('uid') => '5465',
            ('name') => 'Stefanie Mcmohn',
            ('url') => 'urlof5465'
        ),

    (2) => Array
        (
            ('uid') => '40489',
            ('name') => 'Michael',
            ('url') => 'urlof40489'
        )
);

if(array_search('urlof5465', array_column($userdb, 'url')) !== false) {
    echo 'value is in multidim array';
}
else {
    echo 'value is not in multidim array';
}

This idea is in the comments section for array_search() on the PHP manual;

Answer 3

This will work too.

function in_array_r($item , $array){
    return preg_match('/"'.preg_quote($item, '/').'"/i' , json_encode($array));
}

Usage:

if(in_array_r($item , $array)){
    // found!
}

Answer 4

This will do it:

foreach($b as $value)
{
    if(in_array("Irix", $value, true))
    {
        echo "Got Irix";
    }
}

in_array only operates on a one dimensional array, so you need to loop over each sub array and run in_array on each.

As others have noted, this will only for for a 2-dimensional array. If you have more nested arrays, a recursive version would be better. See the other answers for examples of that.

Answer 5

if your array like this

$array = array(
              array("name" => "Robert", "Age" => "22", "Place" => "TN"), 
              array("name" => "Henry", "Age" => "21", "Place" => "TVL")
         );

Use this

function in_multiarray($elem, $array,$field)
{
    $top = sizeof($array) - 1;
    $bottom = 0;
    while($bottom <= $top)
    {
        if($array[$bottom][$field] == $elem)
            return true;
        else 
            if(is_array($array[$bottom][$field]))
                if(in_multiarray($elem, ($array[$bottom][$field])))
                    return true;

        $bottom++;
    }        
    return false;
}

example : echo in_multiarray("22", $array,"Age");

Answer 6

$userdb = Array
(
    (0) => Array
        (
            ('uid') => '100',
            ('name') => 'Sandra Shush',
            ('url') => 'urlof100'
        ),

    (1) => Array
        (
            ('uid') => '5465',
            ('name') => 'Stefanie Mcmohn',
            ('url') => 'urlof5465'
        ),

    (2) => Array
        (
            ('uid') => '40489',
            ('name') => 'Michael',
            ('url') => 'urlof40489'
        )
);

$url_in_array = in_array('urlof5465', array_column($userdb, 'url'));

if($url_in_array) {
    echo 'value is in multidim array';
}
else {
    echo 'value is not in multidim array';
}

Answer 7

For Multidimensional Children: in_array('needle', array_column($arr, 'key'))

For One Dimensional Children: in_array('needle', call_user_func_array('array_merge', $arr))

Answer 8

Great function, but it didnt work for me until i added the if($found) { break; } to the elseif

function in_array_r($needle, $haystack) {
    $found = false;
    foreach ($haystack as $item) {
    if ($item === $needle) { 
            $found = true; 
            break; 
        } elseif (is_array($item)) {
            $found = in_array_r($needle, $item); 
            if($found) { 
                break; 
            } 
        }    
    }
    return $found;
}

Answer 9

You could always serialize your multi-dimensional array and do a strpos:

$arr = array(array("Mac", "NT"), array("Irix", "Linux"));

$in_arr = (bool)strpos(serialize($arr),'s:4:"Irix";');

if($in_arr){
    echo "Got Irix!";
}

Various docs for things I used:

• strpos()
• serialize()
• Type Juggling or (bool)

Answer 10

Since PHP 5.6 there is a better and cleaner solution for the original answer :

With a multidimensional array like this :

$a = array(array("Mac", "NT"), array("Irix", "Linux"))

We can use the splat operator :

return in_array("Irix", array_merge(...$a), true)

---

If you have string keys like this :

$a = array("a" => array("Mac", "NT"), "b" => array("Irix", "Linux"))

You will have to use array_values in order to avoid the error Cannot unpack array with string keys :

return in_array("Irix", array_merge(...array_values($a)), true)

Answer 11

I believe you can just use array_key_exists nowadays:

<?php
$a=array("Mac"=>"NT","Irix"=>"Linux");
if (array_key_exists("Mac",$a))
  {
  echo "Key exists!";
  }
else
  {
  echo "Key does not exist!";
  }
?>

Answer 12

The accepted solution (at the time of writing) by jwueller

function in_array_r($needle, $haystack, $strict = false) {
    foreach ($haystack as $item) {
        if (($strict ? $item === $needle : $item == $needle) || (is_array($item) && in_array_r($needle, $item, $strict))) {
            return true;
        }
    }

    return false;
}

Is perfectly correct but may have unintended behaviuor when doing weak comparison (the parameter $strict = false).

Due to PHP's type juggling when comparing values of different type both

"example" == 0

and

0 == "example"

Evaluates true because "example" is casted to int and turned into 0.

(See Why does PHP consider 0 to be equal to a string?)

If this is not the desired behaviuor it can be convenient to cast numeric values to string before doing a non-strict comparison:

function in_array_r($needle, $haystack, $strict = false) {
    foreach ($haystack as $item) {

        if( ! $strict && is_string( $needle ) && ( is_float( $item ) || is_int( $item ) ) ) {
            $item = (string)$item;
        }

        if (($strict ? $item === $needle : $item == $needle) || (is_array($item) && in_array_r($needle, $item, $strict))) {
            return true;
        }
    }

    return false;
}

Answer 13

This is the first function of this type that I found in the php manual for in_array. Functions in the comment sections aren't always the best but if it doesn't do the trick you can look in there too :)

<?php
function in_multiarray($elem, $array)
    {
        // if the $array is an array or is an object
         if( is_array( $array ) || is_object( $array ) )
         {
             // if $elem is in $array object
             if( is_object( $array ) )
             {
                 $temp_array = get_object_vars( $array );
                 if( in_array( $elem, $temp_array ) )
                     return TRUE;
             }

             // if $elem is in $array return true
             if( is_array( $array ) && in_array( $elem, $array ) )
                 return TRUE;


             // if $elem isn't in $array, then check foreach element
             foreach( $array as $array_element )
             {
                 // if $array_element is an array or is an object call the in_multiarray function to this element
                 // if in_multiarray returns TRUE, than return is in array, else check next element
                 if( ( is_array( $array_element ) || is_object( $array_element ) ) && $this->in_multiarray( $elem, $array_element ) )
                 {
                     return TRUE;
                     exit;
                 }
             }
         }

         // if isn't in array return FALSE
         return FALSE;
    }
?>

Answer 14

Here is my proposition based on json_encode() solution with :

• case insensitive option
• returning the count instead of true
• anywhere in arrays (keys and values)

If word not found, it still returns 0 equal to false.

function in_array_count($needle, $haystack, $caseSensitive = true) {
    if(!$caseSensitive) {
        return substr_count(strtoupper(json_encode($haystack)), strtoupper($needle));
    }
    return substr_count(json_encode($haystack), $needle);
}

Hope it helps.

Answer 15

I was looking for a function that would let me search for both strings and arrays (as needle) in the array (haystack), so I added to the answer by @jwueller.

Here's my code:

/**
 * Recursive in_array function
 * Searches recursively for needle in an array (haystack).
 * Works with both strings and arrays as needle.
 * Both needle's and haystack's keys are ignored, only values are compared.
 * Note: if needle is an array, all values in needle have to be found for it to
 * return true. If one value is not found, false is returned.
 * @param  mixed   $needle   The array or string to be found
 * @param  array   $haystack The array to be searched in
 * @param  boolean $strict   Use strict value & type validation (===) or just value
 * @return boolean           True if in array, false if not.
 */
function in_array_r($needle, $haystack, $strict = false) {
     // array wrapper
    if (is_array($needle)) {
        foreach ($needle as $value) {
            if (in_array_r($value, $haystack, $strict) == false) {
                // an array value was not found, stop search, return false
                return false;
            }
        }
        // if the code reaches this point, all values in array have been found
        return true;
    }

    // string handling
    foreach ($haystack as $item) {
        if (($strict ? $item === $needle : $item == $needle)
            || (is_array($item) && in_array_r($needle, $item, $strict))) {
            return true;
        }
    }
    return false;
}

Answer 16

It works too creating first a new unidimensional Array from the original one.

$arr = array("key1"=>"value1","key2"=>"value2","key3"=>"value3");

foreach ($arr as $row)  $vector[] = $row['key1'];

in_array($needle,$vector);

Answer 17

Shorter version, for multidimensional arrays created based on database result sets.

function in_array_r($array, $field, $find){
    foreach($array as $item){
        if($item[$field] == $find) return true;
    }
    return false;
}

$is_found = in_array_r($os_list, 'os_version', 'XP');

Will return if the $os_list array contains 'XP' in the os_version field.

Answer 18

I found really small simple solution:

If your array is :

Array
(
[details] => Array
    (
        [name] => Dhruv
        [salary] => 5000
    )

[score] => Array
    (
        [ssc] => 70
        [diploma] => 90
        [degree] => 70
    )

)

then the code will be like:

 if(in_array("5000",$array['details'])){
             echo "yes found.";
         }
     else {
             echo "no not found";
          }

Answer 19

I used this method works for any number of nested and not require hacking

<?php
    $blogCategories = [
        'programing' => [
            'golang',
            'php',
            'ruby',
            'functional' => [
                'Erlang',
                'Haskell'
            ]
        ],
        'bd' => [
            'mysql',
            'sqlite'
        ]
    ];
    $it = new RecursiveArrayIterator($blogCategories);
    foreach (new RecursiveIteratorIterator($it) as $t) {
        $found = $t == 'Haskell';
        if ($found) {
           break;
        }
    }

Answer 20

I have found the following solution not very clean code but it works. It is used as an recursive function.

function in_array_multi( $needle, $array, $strict = false ) {
  foreach( $array as $value ) { // Loop thorugh all values
    // Check if value is aswell an array
    if( is_array( $value )) {
      // Recursive use of this function
      if(in_array_multi( $needle, $value )) {
        return true; // Break loop and return true
      }
    } else {
      // Check if value is equal to needle
      if( $strict === true ) {
        if(strtolower($value) === strtolower($needle)) {
          return true; // Break loop and return true
        }
      }else {
        if(strtolower($value) == strtolower($needle)) {
          return true; // Break loop and return true
        }
      }
    }
  }

  return false; // Nothing found, false
}

Answer 21

Please try:

in_array("irix",array_keys($b))
in_array("Linux",array_keys($b["irix"])

Im not sure about the need, but this might work for your requirement

Answer 22

what about array_search? seems it quite faster than foreach according to https://gist.github.com/Ocramius/1290076 ..

if( array_search("Irix", $a) === true) 
{
    echo "Got Irix";
}

Answer 23

you can use like this

$result = array_intersect($array1, $array2);
print_r($result);

http://php.net/manual/tr/function.array-intersect.php