Check if particular value exists in multidimensional array

Question

I have a multidimensional array like this

Array
(
    [jack] => Array
        (
            [0] => 12
            [1] => 45
            [2] => 78
            [3] => 19
            [4] => 94
            [5] => 668
        )

    [john] => Array
        (
            [0] => 641
            [1] => 741
            [2] => 683
            [3] => 603
        )

)

How can i search for 641 and if found return it's parent key. ie. i want to get john if 641 is found.

This is what i have tried

    if(in_array_r("641" , $array)){
    // if found return john!
}

OR

if(in_array_r("12" , $array)){
    // if found return jack!
}

I'm looking for a way that won't include a foreach loop . A solution with less complexity would be nice.

Answer 1

Try this:

$arr = [
    'jack' => [
        12,
        45,
        78,
        19,
        94,
        668,
    ],
    'john' => [
        641,
        741,
        683,
        603,
    ],
];

function in_array_r ($needle, $haystack) {
    foreach ($haystack as $key => $subArr) {
        if (in_array($needle, $subArr)) {
            return $key;
        }
    }
    return false;
}

echo in_array_r(641, $arr); // => john
echo "\n";
echo in_array_r(12, $arr); // => jack

eval.in demo

The code is just running in_array in a foreach. This'll work on 2D arrays, but not on arrays with more dimensions. Let me know if your question is actually about more than 2D arrays.

Answer 2

Best Way To Find is As Follow

<?php

$myarr = Array
(
'Jack' => Array
    (
        'uid' => '100',
        'name' => 'Sandra Shush',
        'url' => 'urlof100'
    ),

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

echo checkData($myarr,100);

 function checkData( $myarr,$myvalue ) 
 {
        foreach( $myarr as $key => $value ){
            if( in_array(  $myvalue, $value ) ){
                return $key;
            }
        }
        return false;
 }

Check It http://phptester.net/

Answer 3

I'm assuming you made use of a recursive in_array function as from here: https://gist.github.com/Billy-/bc6865066981e80e097f

I have modified it to suit your requirement here (so it returns key of array now as you desired):

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, $strict)!==FALSE)) {
            return key($haystack);
        }
    }

    return false;
}

You should be able to use this as:

echo in_array_r('641',$array); // Prints john
echo in_array_r('12',$array); // Prints jack

Where the array I'm assuming is as of your question:

Array
(
    [jack] => Array
        (
            [0] => 12
            [1] => 45
            [2] => 78
            [3] => 19
            [4] => 94
            [5] => 668
        )

    [john] => Array
        (
            [0] => 641
            [1] => 741
            [2] => 683
            [3] => 603
        )

)

Answer 4

$arr = Array(
    "jack" => Array(12, 45, 78, 19, 94, 668),
    "john" => Array("641", 741, 683, 603),
);
$tofind = 641;

function getKey($arr, $tofind) {
    foreach($arr as $key => $val){
        if(in_array($tofind, $val)){
            return $key;
        }
    }
    return "not found";
}

echo getKey($arr, $tofind);