How to Get All Keys of an Multi Level Associative Arrays in PHP

Can I get all keys of an multi level associative arrays in php

Dereleased's solution will be faster I guess (as it uses internal loops), mine can also deal with array values for object_id keys. Your tradeoff ;)

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function find_all($needle, array $haystack, array &$result = null) {
    // This is to initialize the result array and is only needed for
    // the first call of this function
    if(is_null($result)) {
        $result = array();
    }
    foreach($haystack as $key => $value) {
        // Check whether the key is the value we are looking for. If the value
        // is not an array, add it to the result array.
        if($key === $needle && !is_array($value)) {
            $result[] = $value;
        }
        if(is_array($value)) {
            // If the current value is an array, we perform the same
            // operation with this 'subarray'.
            find_all($needle, $value, $result);
        }
    }
    // This is only needed in the first function call to retrieve the results
    return $result;
}

As you can see, the result array is given to every call of the function as reference (denoted by the &). This way, every recursive call of this function has access to the same array and can just add a find.

You can do:

$values = find_all('object_id', $array);

It gives me for your array:

Array
(
    [0] => 12061
    [1] => 100012061
    [2] => 1000000000015
    [3] => 10001
    [4] => 12862
    [5] => 12876
    [6] => 1206102000
    [7] => 1206104000
    [8] => 1206101000
    [9] => 1206105000
    [10] => 1206106000
    [11] => 10017
    [12] => 100010017
    [13] => 300306
    [14] => 12894
    [15] => 12862
    [16] => 12876
    [17] => 1001701000
    [18] => 11990
    [19] => 100011990
    [20] => 12862
    [21] => 12876
    [22] => 10017
    [23] => 12894
)

Find key of a multi-dimensional associative array by value in php

You should consider changing structure of array. As your ID is not unique, elements with same ID stay in one array.

$main_array = array(
    1001 => array(
        array('name' => 'test1'),
        array('name' => 'test3'),
    ),
    1002 => array(
        array('name' => 'test2'),
    )
);

So

print_r( $main_array[1001] );

would give you

Array
(
    [0] => Array
        (
            [name] => test1
        )

    [1] => Array
        (
            [name] => test3
        )

)

If this is not possible, you have to loop over the entire array to achieve this.

function arraySearchId( $id, $array ) {
    $results = array();
    foreach ( $array as $key => $val ) {
        if ( $val['id'] === $id ) {
            $results[] = $key;
        }
    }
    return $results;
}

echo '<pre>';
print_r( arraySearchId( 1001, $main_array ) );
echo '</pre>';

Result:

Array
(
    [0] => 0
    [1] => 2
)

How to get an array of specific key in multidimensional array without looping

Since PHP 5.5, you can use array_column:

$ids = array_column($users, 'id');

This is the preferred option on any modern project. However, if you must support PHP<5.5, the following alternatives exist:

Since PHP 5.3, you can use array_map with an anonymous function, like this:

$ids = array_map(function ($ar) {return $ar['id'];}, $users);

Before ^{_{(Technically PHP 4.0.6+)}}, you must create an anonymous function with create_function instead:

$ids = array_map(create_function('$ar', 'return $ar["id"];'), $users);

Iterate through every single key and value in a multi-dimensional associative array PHP

The foreach statement has the option of iterating over just the values, as you're doing, or the keys and values. I suspect this is what you're looking for:

foreach ($arr6 as $k=>$test) {
  echo $k . '<br>';
    foreach ($test as $k1=>$testing1) {
      echo '  ' . $k1 . '<br>';
      foreach ($testing1 as $k2=>$testing2) {
        echo '    ' . $testing2 . '<br>';
    }
  }
}

The notices you're getting are because you're trying to use echo on an array, which is not possible.

Find all second level keys in multi-dimensional array in php

<?php

// Gets a list of all the 2nd-level keys in the array
function getL2Keys($array)
{
    $result = array();
    foreach($array as $sub) {
        $result = array_merge($result, $sub);
    }        
    return array_keys($result);
}

?>

edit: removed superfluous array_reverse() function

php 7 - sort multilevel associative array by keys to have it sorted on each level lexicographically

Finally, solved it.

$a = ['c'=>['d'=>1, 'a'=>2], 'b'=>['b'=>3, 'a'=>4], 'a'=>['z','x','y']];

function array_sort_recursive($arr) {
    foreach ($arr as $key => $val) {
        if (is_array($val))
            $arr[$key] = array_sort_recursive($val);
    }
    uksort($arr, "strcmp");
    return $arr;
}

$b = array_sort_recursive($a);
print_r($b);

Try it: here

PHP - Get a count of Multi-dimensional arrays within an associative array and indexed arrays

The following line of code reproduce your multidimensional array for test purpose:

 $arrs=array_fill_keys(['name'],array_fill(0,49,['key1'=>1,'key2'=>2,'key3'=>2,]));

According to this:

49 - (indexed arrays within associative array 'Name')

147 - (total key-value pairs within indexed array)

3 - (key-value pairs within an indexed array)

and specifically the third line,all your counts are simplified to some simple operations that you can achieve this way:

$InArWiAsArNa=count($arrs['name']);
$KV_wi_IA=count(current($arrs['name']));
$total_KV_pairs_wi_IA=$InArWiAsArNa*$KV_wi_IA;

var_dump($InArWiAsArNa,$total_KV_pairs_wi_IA,$KV_wi_IA);

output:

int(49)
int(147)
int(3)

however if you remove the third condition, for example if the key-value pairs within an indexed array number is variable, this mean you don't need it anymore so you should loop through the array to get the two first answers:

$InArWiAsArNa=0;
$total_KV_pairs_wi_IA=0;
foreach($arrs['name'] as $key=>$val){
    $InArWiAsArNa ++;
    $total_KV_pairs_wi_IA+=count($val);  
}

var_dump($InArWiAsArNa,$total_KV_pairs_wi_IA);

output:

 int(49)
 int(147)

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