CODEWITHSUNDEEP
phparraysjsonassociative-array
kittygirl
kittygirl

Reputation: 2443

PHP `json_encode` incorrectly turn array into `{}`

My system is centos 7.4 with PHP 5.4 

$s='a:91:{s:13:"spotsviewvars";s:7:"1916.74";s:13:"100000T18vars";N;s:17:"100000T18S106vars";s:7:"1746.95";s:17:"100000T18S107vars";s:4:"4.49";s:17:"100000T18S108vars";s:4:"8.29";s:17:"100000T18S109vars";s:4:"4.38";s:17:"100000T18S110vars";s:3:"5.4";s:17:"100000T18S111vars";s:4:"3.88";s:17:"100000T18S112vars";s:4:"3.49";s:17:"100000T18S113vars";s:4:"5.55";s:17:"100000T18S114vars";s:4:"3.58";s:17:"100000T18S115vars";s:3:"5.5";s:17:"100000T18S116vars";s:5:"10.39";s:17:"100000T18S117vars";s:4:"6.52";s:17:"100000T18S118vars";s:4:"6.09";s:17:"100000T18S119vars";s:3:"6.7";s:17:"100000T18S120vars";s:4:"4.18";s:17:"100000T18S121vars";s:5:"14.81";s:17:"100000T18S122vars";s:3:"3.9";s:17:"100000T18S123vars";s:4:"4.93";s:17:"100000T18S124vars";s:4:"4.06";s:17:"100000T18S125vars";s:4:"5.03";s:17:"100000T18S126vars";s:4:"5.73";s:17:"100000T18S127vars";s:4:"3.13";s:17:"100000T18S128vars";s:3:"7.2";s:17:"100000T18S129vars";s:4:"7.03";s:17:"100000T18S130vars";s:4:"3.81";s:17:"100000T18S131vars";s:3:"7.4";s:17:"100000T18S132vars";s:4:"7.82";s:17:"100000T18S133vars";s:4:"3.96";s:13:"100000T19vars";N;s:17:"100000T19S134vars";N;s:17:"100000T19S135vars";N;s:17:"100000T19S136vars";N;s:17:"100000T19S137vars";s:5:"12.54";s:17:"100000T19S138vars";N;s:17:"100000T19S139vars";N;s:17:"100000T19S140vars";N;s:17:"100000T19S141vars";N;s:17:"100000T19S142vars";N;s:17:"100000T19S143vars";N;s:17:"100000T19S144vars";N;s:17:"100000T19S145vars";N;s:17:"100000T19S146vars";N;s:17:"100000T19S147vars";N;s:17:"100000T19S148vars";N;s:17:"100000T19S149vars";N;s:13:"100000T18S106";s:2:"A2";s:13:"100000T18S107";s:2:"A2";s:13:"100000T18S108";s:2:"A2";s:13:"100000T18S109";s:2:"A2";s:13:"100000T18S110";s:2:"A2";s:13:"100000T18S111";s:2:"A2";s:13:"100000T18S112";s:2:"A2";s:13:"100000T18S113";s:2:"A2";s:13:"100000T18S114";s:2:"A2";s:13:"100000T18S115";s:2:"A2";s:13:"100000T18S116";s:2:"A2";s:13:"100000T18S117";s:2:"A2";s:13:"100000T18S118";s:2:"A1";s:13:"100000T18S119";s:2:"A2";s:13:"100000T18S120";s:2:"A1";s:13:"100000T18S121";s:2:"A1";s:13:"100000T18S122";s:2:"A2";s:13:"100000T18S123";s:2:"A2";s:13:"100000T18S124";s:2:"A2";s:13:"100000T18S125";s:2:"A2";s:13:"100000T18S126";s:2:"A1";s:13:"100000T18S127";s:2:"A2";s:13:"100000T18S128";s:2:"A1";s:13:"100000T18S129";s:2:"A1";s:13:"100000T18S130";s:2:"A2";s:13:"100000T18S131";s:2:"A2";s:13:"100000T18S132";s:2:"A1";s:13:"100000T18S133";s:2:"A2";s:13:"100000T19S134";N;s:13:"100000T19S135";N;s:13:"100000T19S136";N;s:13:"100000T19S137";s:0:"";s:13:"100000T19S138";N;s:13:"100000T19S139";N;s:13:"100000T19S140";N;s:13:"100000T19S141";N;s:13:"100000T19S142";N;s:13:"100000T19S143";N;s:13:"100000T19S144";N;s:13:"100000T19S145";N;s:13:"100000T19S146";N;s:13:"100000T19S147";N;s:13:"100000T19S148";N;s:13:"100000T19S149";N;}';
$s_array=unserialize($s);
var_dump($s_array);
$s_json=json_encode($s_array,JSON_HEX_QUOT|JSON_HEX_TAG|JSON_HEX_AMP|JSON_HEX_APOS|JSON_UNESCAPED_UNICODE);
var_dump($s_json);

You will notice strange result when run above PHP script.

$s_array is array,json_encode result should be something like [],but result is {}.
What's the problem?

Upvotes: 0

Views: 84

Answers (2)

Quentin
Quentin

Reputation: 943561

You appear to just have been confused by differences in terminology.

In PHP an "array" can either be an indexed array (in which you have a sequence of values) or an associative array (in which you have name => value pairs).

In JSON a sequence of values is stored in an array, and a set of name => value pairs is stored in an object.

Since you have name => value pairs in your data, you get an object when converting it to JSON.

For comparison:

$indexed_array = [ "foo", "bar", "baz" ];
$associative_array = [ "foo" => "A", "bar" => "B", "baz" => "C" ];
print json_encode($indexed_array);
print "\n";
print json_encode($associative_array);

Upvotes: 2

ADyson
ADyson

Reputation: 61904

The code is working exactly as it should.

What you've got there is an associative array - i.e. each entry has a name (like "spotsviewvars", or "100000T18vars" rather than a numeric index (like 0 or 1). It's effectively a set of key/value pairs.

So in order to preserve that information when encoding as JSON, it has to be turned into an object instead - JSON has no concept of associative arrays. The only possible JSON representation which keeps both the key (e.g. "spotsviewvars") and the associated value (e.g. "1916.74") is an object.

If you turned it into a plain array you'd lose the key information, which I would assume is important. Every value would just have a numeric index to hold it instead, and you wouldn't know what its original meaning was.

Upvotes: 0

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