PHP has built in function http_build_query that can be used to prepare a query string from an array.
Instead of explicitly appending elements to string, this function comes handy, which takes cares of generating URL-encoded query string either from an associative or indexed array.
Laravel provide a helper Arr::query() to build query string from an array, an alternative to core php http_build_query() method.
Tested with Laravel versions 5.8, 6 and 7.
Kindly check for your version on official helpers page.