How to convert an array to a string in PHP?

I would turn it into CSV form, like so:

$string_version = implode(',', $original_array)

You can turn it back by doing:

$destination_array = explode(',', $string_version)

I would turn it into a json object, with the added benefit of keeping the keys if you are using an associative array:

 $stringRepresentation= json_encode($arr);