PHP Multidimensional Array Searching (Find key by specific value)

PhpSearchMultidimensional ArrayKey

Php Problem Overview

I have this multidimensional array. I need to search it and return only the key that matches the value of the "slug". I know there are other threads about searching multidimensional arrays, but I'm not really understanding enough to apply to my situation. Thanks very much for any help!

So I need a function like:

myfunction($products,'breville-one-touch-tea-maker-BTM800XL');
// returns 1

Here's the Array:

$products = array (
1  => array(
		'name' 			=> 'The Breville One-Touch Tea Maker',
		'slug'			=> 'breville-one-touch-tea-maker-BTM800XL',
		'shortname'		=> 'The One-Touch Tea Maker',
		'listprice' 	=> '299.99',
		'price' 		=> '249.99',
		'rating' 		=> '9.5',
		'reviews' 		=> '81',
		'buyurl' 		=> 'http://www.amazon.com/The-Breville-One-Touch-Tea-Maker/dp/B003LNOPSG',
		'videoref1' 	=> 'xNb-FOTJY1c',
		'videoref2'		=> 'WAyk-O2B6F8',
		'image' 		=> '812BpgHhjBML.jpg',
		'related1' 		=> '2',
		'related2' 		=> '3',
		'related3' 		=> '4',
		'bestbuy'		=> '1',
		'quote'			=> '',
		'quoteautor'	=> 'K. Martino',
		),
		
2  => array(
		'name' 			=> 'Breville Variable-Temperature Kettle BKE820XL',
		'slug'			=> 'breville-variable-temperature-kettle-BKE820XL',
		'shortname'		=> 'Variable Temperature Kettle',
		'listprice' 	=> '199.99',
		'price' 		=> '129.99',
		'rating' 		=> '9',
		'reviews' 		=> '78',
		'buyurl' 		=> 'http://www.amazon.com/Breville-BKE820XL-Variable-Temperature-1-8-Liter-Kettle/dp/B001DYERBK',
		'videoref1' 	=> 'oyZWBD83xeE',
		'image' 		=> '41y2B8jSKmwL.jpg',
		'related1' 		=> '3',
		'related2' 		=> '4',
		'related3' 		=> '5',
		'bestbuy'		=> '1',
		'quote'			=> '',
		'quoteautor'	=> '',
		),
);

Php Solutions

Solution 1 - Php

Another poossible solution is based on the array_search() function. You need to use PHP 5.5.0 or higher.

Example

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

(1) => Array
    (
        (uid) => '5465',
        (name) => 'Stefanie Mcmohn',
        (pic_square) => 'urlof100'
    ),

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

$key = array_search(40489, array_column($userdb, 'uid'));

echo ("The key is: ".$key);
//This will output- The key is: 2

Explanation

The function array_search() has two arguments. The first one is the value that you want to search. The second is where the function should search. The function array_column() gets the values of the elements which key is 'uid'.

Summary

So you could use it as:

array_search('breville-one-touch-tea-maker-BTM800XL', array_column($products, 'slug'));

or, if you prefer:

// define function
function array_search_multidim($array, $column, $key){
    return (array_search($key, array_column($array, $column)));
}

// use it
array_search_multidim($products, 'slug', 'breville-one-touch-tea-maker-BTM800XL');

The original example(by xfoxawy) can be found on the DOCS.
The array_column() page.

Update

Due to Vael comment I was curious, so I made a simple test to meassure the performance of the method that uses array_search and the method proposed on the accepted answer.

I created an array which contained 1000 arrays, the structure was like this (all data was randomized):

[
      {
            "_id": "57fe684fb22a07039b3f196c",
            "index": 0,
            "guid": "98dd3515-3f1e-4b89-8bb9-103b0d67e613",
            "isActive": true,
            "balance": "$2,372.04",
            "picture": "http://placehold.it/32x32",
            "age": 21,
            "eyeColor": "blue",
            "name": "Green",
            "company": "MIXERS"
      },...
]

I ran the search test 100 times searching for different values for the name field, and then I calculated the mean time in milliseconds. Here you can see an example.

Results were that the method proposed on this answer needed about 2E-7 to find the value, while the accepted answer method needed about 8E-7.

Like I said before both times are pretty aceptable for an application using an array with this size. If the size grows a lot, let's say 1M elements, then this little difference will be increased too.

Update II

I've added a test for the method based in array_walk_recursive which was mentionend on some of the answers here. The result got is the correct one. And if we focus on the performance, its a bit worse than the others examined on the test. In the test, you can see that is about 10 times slower than the method based on array_search. Again, this isn't a very relevant difference for the most of the applications.

Update III

Thanks to @mickmackusa for spotting several limitations on this method:

  • This method will fail on associative keys.

  • This method will only work on indexed subarrays (starting from 0 and have consecutively ascending keys).

Solution 2 - Php

Very simple:

function myfunction($products, $field, $value)
{
   foreach($products as $key => $product)
   {
      if ( $product[$field] === $value )
         return $key;
   }
   return false;
}

Solution 3 - Php

This class method can search in array by multiple conditions:

class Stdlib_Array
{
    public static function multiSearch(array $array, array $pairs)
    {
        $found = array();
        foreach ($array as $aKey => $aVal) {
            $coincidences = 0;
            foreach ($pairs as $pKey => $pVal) {
                if (array_key_exists($pKey, $aVal) && $aVal[$pKey] == $pVal) {
                    $coincidences++;
                }
            }
            if ($coincidences == count($pairs)) {
                $found[$aKey] = $aVal;
            }
        }

        return $found;
    }    
}

// Example:

$data = array(
    array('foo' => 'test4', 'bar' => 'baz'),
    array('foo' => 'test',  'bar' => 'baz'),
    array('foo' => 'test1', 'bar' => 'baz3'),
    array('foo' => 'test',  'bar' => 'baz'),
    array('foo' => 'test',  'bar' => 'baz4'),
    array('foo' => 'test4', 'bar' => 'baz1'),
    array('foo' => 'test',  'bar' => 'baz1'),
    array('foo' => 'test3', 'bar' => 'baz2'),
    array('foo' => 'test',  'bar' => 'baz'),
    array('foo' => 'test',  'bar' => 'baz'),
    array('foo' => 'test4', 'bar' => 'baz1')
);

$result = Stdlib_Array::multiSearch($data, array('foo' => 'test4', 'bar' => 'baz1'));

var_dump($result);

Will produce:

array(2) {
  [5]=>
  array(2) {
    ["foo"]=>
    string(5) "test4"
    ["bar"]=>
    string(4) "baz1"
  }
  [10]=>
  array(2) {
    ["foo"]=>
    string(5) "test4"
    ["bar"]=>
    string(4) "baz1"
  }
}

Solution 4 - Php

Use this function:

function searchThroughArray($search,array $lists){
        try{
            foreach ($lists as $key => $value) {
                if(is_array($value)){
                    array_walk_recursive($value, function($v, $k) use($search ,$key,$value,&$val){
                        if(strpos($v, $search) !== false )  $val[$key]=$value;
                    });
            }else{
                    if(strpos($value, $search) !== false )  $val[$key]=$value;
                }
    
            }
            return $val;
    
        }catch (Exception $e) {
            return false;
        }
    }

and call function.

print_r(searchThroughArray('breville-one-touch-tea-maker-BTM800XL',$products));

Solution 5 - Php

function search($array, $key, $value) 
{ 
    $results = array(); 

    if (is_array($array)) 
    { 
        if (isset($array[$key]) && $array[$key] == $value) 
            $results[] = $array; 

        foreach ($array as $subarray) 
            $results = array_merge($results, search($subarray, $key, $value)); 
    } 

    return $results; 
}

Solution 6 - Php

I would do like below, where $products is the actual array given in the problem at the very beginning.

print_r(
  array_search("breville-variable-temperature-kettle-BKE820XL", 
  array_map(function($product){return $product["slug"];},$products))
);

Solution 7 - Php

Try this

function recursive_array_search($needle,$haystack) {
        foreach($haystack as $key=>$value) {
            $current_key=$key;
            if($needle==$value['uid'] OR (is_array($value) && recursive_array_search($needle,$value) !== false)) {
                return $current_key;
            }
        }
        return false;
    }

Solution 8 - Php

For the next visitor coming along: use the recursive array walk; it visits every "leaf" in the multidimensional array. Here's for inspiration:

function getMDArrayValueByKey($a, $k) {
	$r = [];
	array_walk_recursive ($a, 
	                      function ($item, $key) use ($k, &$r) {if ($key == $k) $r[] = $item;}
	                      );
	return $r;
}

Solution 9 - Php

You can convert the array to JSON and search as a string then return the found object, so no matter how deeply nested it'll find it quickly:

function findObjectByKeyValue($array, $key, $value){
    $object = [];
    $string = json_encode($array);
    $foundPosition = strpos($string, '"' . $key . '":"' . $value . '"');

    if( $foundPosition ){
        $prevBracketPos = strrpos(substr($string, 0, $foundPosition), '{');

        if( $prevBracketPos ){
            $nextBracketPos = strpos($string, '}', $foundPosition);

            if( $nextBracketPos ){
                $brackets = 0;

                while( strpos(substr($string, $foundPosition, $nextBracketPos - $foundPosition), '{') &&
                        substr_count(substr($string, $foundPosition, $nextBracketPos - $foundPosition), '{') > $brackets
                    ){
                    $lenToAdd = strlen(substr($string, $foundPosition, $nextBracketPos - $foundPosition + 1));
                    $nextBracketPos = strpos($string, '}', $foundPosition + $lenToAdd);
                    $brackets++;
                }

                $substr = substr($string, $prevBracketPos, $nextBracketPos - $prevBracketPos + 1);

                // Confirm it's wrapped with brackets before we decode
                if( substr($substr, 0, 1) === '{' && substr($substr, -1, 1) === '}' ){
                    $object = json_decode($substr, true);
                }
            }
        }
    }

    return $object;
}

Example:

$arr = [{
    "items":
    {
        "1": [
        {
            "id": "621eaf06062cd",
            "nestedItem":
            {
                "id": "123",
                "nestedItem":
                {
                    "id": "456",
                    "nestedItem":
                    {
                        "id": "789"
                    }
                }
            }
        }],
        "2": [
        {
            "id": "621eb58de7364",
        }],
        "3": [
        {
            "id": "62226910716af",
        }]
    }
}];

echo findObjectByKeyValue($arr, 'id', '123');
/* {
    "id": "123",
    "nestedItem":
    {
        "id": "456",
        "nestedItem":
        {
            "id": "789"
        }
    }
} /*

echo findObjectByKeyValue($arr, 'id', '621eaf06062cd');
/* {
    "id": "621eaf06062cd",
    "nestedItem":
    {
        "id": "123",
        "nestedItem":
        {
            "id": "456",
            "nestedItem":
            {
                "id": "789"
            }
        }
    }
} */

The only problem уоu could run into is if there're brackets within as strings in the array.

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