note 126787 added to function.json-decode

JSON can be decoded to PHP arrays by using the $associative = true option. Be wary that associative arrays in PHP can be a "list" or "object" when converted to/from JSON, depending on the keys (of absence of them). You would expect that recoding and re-encoding will always yield the same JSON string, but take this example: $json = '{"0": "No", "1": "Yes"}'; $array = json_decode($json, true); // decode as associative hash print json_encode($array) . PHP_EOL; This will output a different JSON string than the original: ["No","Yes"] The object has turned into an array! Similarly, a array that doesn't have consecutive zero based numerical indexes, will be encoded to a JSON object instead of a list. $array = [ 'first', 'second', 'third', ]; print json_encode($array) . PHP_EOL; // remove the second element unset($array[1]); print json_encode($array) . PHP_EOL; The output will be: ["first","second","third"] {"0":"first","2":"third"} The array has turned into an object! In other words, decoding/encoding to/from PHP arrays is not always symmetrical, or might not always return what you expect! On the other hand, decoding/encoding from/to stdClass objects (the default) is always symmetrical. Arrays may be somewhat easier to work with/transform than objects. But especially if you need to decode, and re-encode json, it might be prudent to decode to objects and not arrays. If you want to enforce an array to encode to a JSON list (all array keys will be discarded), use: json_encode(array_values($array)); If you want to enforce an array to encode to a JSON object, use: json_encode((object)$array); See also: https://www.php.net/manual/en/function.array-is-list.php ---- Server IP: 45.112.84.4 Probable Submitter: 80.90.5.135 (proxied: 80.56.250.62) ---- Manual Page -- https://php.net/manual/en/function.json-decode.php Edit -- https://main.php.net/note/edit/126787 Del: integrated -- https://main.php.net/note/delete/126787/integrated Del: useless -- https://main.php.net/note/delete/126787/useless Del: bad code -- https://main.php.net/note/delete/126787/bad+code Del: spam -- https://main.php.net/note/delete/126787/spam Del: non-english -- https://main.php.net/note/delete/126787/non-english Del: in docs -- https://main.php.net/note/delete/126787/in+docs Del: other reasons-- https://main.php.net/note/delete/126787 Reject -- https://main.php.net/note/reject/126787 Search -- https://main.php.net/manage/user-notes.php