Recursive array_search

Question

I have a multi-dimensional array:

$categories = array(
    array(
        'CategoryID' => 14308,
        'CategoryLevel' => 1,
        'CategoryName' => 'Alcohol & Food',
        'CategoryParentID' => 14308
    ),
    // CHILD CATEGORIES
    array(
        array(
            'CategoryID' => 179836,
            'CategoryLevel' => 2,
            'CategoryName' => 'Alcohol & Alcohol Mixes',
            'CategoryParentID' => 14308
        ),
        array(
            array(
                'CategoryID' => 172528,
                'CategoryLevel' => 2,
                'CategoryName' => 'Antipasto, Savoury',
                'CategoryParentID' => 14308
            )
        )
    )
);

I need to get the exact location of the index, and since array_search doesn't work on multi-dimensional arrays, I'm using one of the functions provided on the PHP manual page.

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

.. but it also returns the key of the first array only:

echo recursive_array_search(172528, $categories); // outputs 1

I'm expecting:

[1][1][0]

Pieter De Schepper · Accepted Answer · 2015-02-12 08:57:27Z

19

You can change your recursive function like this, which should give you the solution:

function recursive_array_search($needle, $haystack, $currentKey = '') {
    foreach($haystack as $key=>$value) {
        if (is_array($value)) {
            $nextKey = recursive_array_search($needle,$value, $currentKey . '[' . $key . ']');
            if ($nextKey) {
                return $nextKey;
            }
        }
        else if($value==$needle) {
            return is_numeric($key) ? $currentKey . '[' .$key . ']' : $currentKey . '["' .$key . '"]';
        }
    }
    return false;
}

This will result in

[1][1][0]["CategoryID"]

Since CategoryID is also a key in your multidimensional array.

If you don't want this, you can adapt the function to

function recursive_array_search($needle, $haystack, $currentKey = '') {
    foreach($haystack as $key=>$value) {
        if (is_array($value)) {
            $nextKey = recursive_array_search($needle,$value, $currentKey . '[' . $key . ']');
            if ($nextKey) {
                return $nextKey;
            }
        }
        else if($value==$needle) {
            return is_numeric($key) ? $currentKey . '[' .$key . ']' : $currentKey;
        }
    }
    return false;
}

answered Feb 12, 2015 at 8:57

Pieter De Schepper

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2 Comments

eozzy Over a year ago

Thanks heaps, that works. Sorry for the stupid question, but if I want to print the value of that fetched index, I can't print with $categories.$key, it just prints the categories and then the string literally.

Alex McCabe Over a year ago

I can't figure this out either, anyone?

Oswald · Accepted Answer · 2015-02-12 10:35:35Z

3

You are ignoring the returned value of your inner call to recursive_array_search. Don't do that.

/*
 * Searches for $needle in the multidimensional array $haystack.
 *
 * @param mixed $needle The item to search for
 * @param array $haystack The array to search
 * @return array|bool The indices of $needle in $haystack across the
 *  various dimensions. FALSE if $needle was not found.
 */
function recursive_array_search($needle,$haystack) {
    foreach($haystack as $key=>$value) {
        if($needle===$value) {
            return array($key);
        } else if (is_array($value) && $subkey = recursive_array_search($needle,$value)) {
            array_unshift($subkey, $key);
            return $subkey;
        }
    }
}

edited Feb 12, 2015 at 10:35

answered Feb 12, 2015 at 9:02

Oswald

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1 Comment

robertaodj Over a year ago

Hello. In array ["name" => "class_test", "static" => true, "public" => true, "interface" => false] the return is [0 => "static"], namely only returns the first element found. Returning all with this solution? [0 => "static", 1 => "public"]

Oleksandr P. · Accepted Answer · 2018-07-16 12:51:31Z

0

public static function unique(array $data, $key){
    $rez = [];
    foreach($data as $val){
        if(!isset($val[$key]) && is_array($val)){
            return self::unique($val, $key);
        }elseif( isset($val[$key]) ){
            $rez[] = $val[$key];
        }
    }
    return array_unique($rez);
}

answered Jul 16, 2018 at 12:51

Oleksandr P.

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Comments

RobC · Accepted Answer · 2019-09-24 12:22:01Z

function array_search_recursive( $search, $values = array(), $i = 0) {
    $match = false;
    var_dump($i, $search);
    $i++;
    foreach ( $values as $keyState => $val ) {
        var_dump($val == $search, 'expression');
        if ( $val == $search ) {
            return $keyState;
        }
        if ( is_array( $val ) ) {
            $match = array_search_recursive($search, $val, $i);
        }
        if ( $match !== false ) {
            return $keyState;
        }
    }

    return false;
}

echo array_search_recursive($search, $canada)

Edit:

This will return the first key, tested for $canada = array( 'Brazilia' => 'test1', "Alberta" => [ "Airdrie", "Brooks", "Camrose" ], "British Columbia" => [ "Abbotsford" => [ 'a', 'b', 'c' ], "Armstrong", "Castlegar" ], "Manitoba" => [ "Brandon", "Selkirk" ], 'Olanda' => 'test2' ); $search = "Selkirk";

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