Loop through nested array php and prefix value

Question

Reads all the prefix value in an array. If slug value is modules the result would be api/v1/tenants/modules/{id}, in contrast if slug value fetch the result would be api/v1/tenants/fetch/{id}.

        "slug" => "api",
        "children" => [
            "prefix" => "v1",
            "slug" => "v1",
            "children" => [
                "prefix" => "tenants",
                "slug" => "tenants",
                "children" => [
                    [
                        "prefix" => "fetch/{id}",
                        "slug" => "fetch",
                    ],
                    [
                        "prefix" => "modules/{id}",
                        "slug" => "modules",
                    ]


                ],
            ],
        ],

Answer 1

You can use array_walk_recursive to traverse array recursively,

$res = [];
// & so that it keeps data of $res in every loop
array_walk_recursive($arr, function ($item, $key) use (&$res) {
    if ($key == 'prefix') {
        $res[] = $item; // fetching only prefix values recursively
    }

});
// this is your generated url
echo implode("/", $res);

Demo .

Output :

api/v1/tenants/modules/{id}

Answer 2

I use array-walk-recursive as:

function getPrefix($v, $k) { global $ps; if ($k == "prefix") $ps[] = $v; }
array_walk_recursive($arr, 'getPrefix');

Now, $ps is array of the prefix. Then you can use implode to add the /

Live example: 3v4l