使用键名称数组在多维数组中添加/编辑值

I have an array of key names of variable length and I want to use those names to assign a value to an array

for example, I have an array that lists the number of cars and bikes of different makes:

$vehicles = [
    'cars' => Array
    (
        'suzuki' => Array
        (
            'wagon' => 4,
            'baleno' => 2
        ),
        'honda' => Array
        (
            'civic' => 6
        )
    ),
    'bikes' => array
    (
        'raleigh' => 3,
        'scott' => 3
    )
];

I also have several arrays of key names along with values to put in the main array:

$keys1 = ['cars', 'honda', 'jazz'];
$value1 = 3;
$keys2 = ['bikes', 'scott'];
$value2 = 1;
$keys3 = ['motorbikes', 'harley-davidson', 'dyna', 'street-bob'];
$value3 = 2;

After inputting all these values the array should look like this:

$vehicles = [
    'cars' => Array
    (
        'suzuki' => Array
        (
            'wagon' => 4,
            'baleno' => 2
        ),
        'honda' => Array
        (
            'civic' => 6,
            'jazz' => 3
        )
    ),
    'bikes' => array
    (
        'raleigh' => 3,
        'scott' => 1
    ),
    'motorbikes' => Array
    (
        'harley-davidson' => Array
        (
            'dyna' => Array
            (
                'street-bob' => 2
            )
        )
    )
];

So the first array adds a $key => $value pair where there wasn't one before. The second one replaces the value of the key at the end of $array2 and the last one creates a new array when there isn't one to begin with.

How can I populate the array in this way?

eval() would solve all my problems but the arrays are created from html and so it is a huge security risk.

You could transform your $keys array in the same format as your $vehicles and then replace them recursively :

$vehicles = [
    'cars' => [
        'suzuki' => [
            'wagon'  => 1,
            'boleno' => 2
        ]
    ],

    'bikes' => [
        'scott' => 3
    ]

];

$keys = ['cars', 'honda', 'jazz'];
$value  = 3;

function addValues($vehicles, $keys, $value)
{
    $formatted = formatArray($keys, $value);

    return array_replace_recursive($vehicles, $formatted);
}

function formatArray($array, $value)
{
    $format = function ($carry, $item) {
        return [$item => $carry];
    };

    return array_reduce(array_reverse($array), $format, $value);
}

$vehicles = addValues($vehicles, $keys, $value);
var_dump($vehicles);

Output:

array (size=2)
  'cars' => 
    array (size=2)
      'suzuki' => 
        array (size=2)
          'wagon' => int 1
          'boleno' => int 2
      'honda' => 
        array (size=1)
          'jazz' => int 3
  'bikes' => 
    array (size=1)
      'scott' => int 3

The convenient way(on my opinion) to construct a key/value pairs list would be as the following:

// $vehicles is your initial array

$key_paths = [
  ['key_path' =>  ['cars', 'honda', 'jazz'], 'value' => 3],
  ['key_path' =>  ['bikes', 'scott'], 'value' => 1],
  ['key_path' =>  ['motorbikes', 'harley-davidson', 'dyna', 'street-bob'], 'value' => 2],
];

And here is the solution using array_slice function and references:

foreach ($key_paths as $kPath) {
    $current = null;
    foreach (array_slice($kPath['key_path'], 0, -1) as $key) {
        if (is_null($current)) {
            if (!isset($vehicles[$key])) $vehicles[$key] = [];
            $current = &$vehicles[$key];
        } else {
            if (!isset($current[$key])) $current[$key] = [];
            $current = &$current[$key];
        }
    }
    $current[end($kPath['key_path'])] = $kPath['value'];
    unset($current);    // unsetting reference
}

print_r($vehicles);

The output:

Array
(
    [cars] => Array
        (
            [suzuki] => Array
                (
                    [wagon] => 4
                    [baleno] => 2
                )

            [honda] => Array
                (
                    [civic] => 6
                    [jazz] => 3
                )
        )

    [bikes] => Array
        (
            [raleigh] => 3
            [scott] => 1
        )

    [motorbikes] => Array
        (
            [harley-davidson] => Array
                (
                    [dyna] => Array
                        (
                            [street-bob] => 2
                        )
                )
        )
)