I was trying to get some values from MySQL database and when converting into JSON array using json_encode() I got a JSON object , after a while I found out that the indices was the root cause of the problem
here's the example I mentioned
<?php
$array = array(0=>"zero",2=>"two");
$another_array=array(0=>"zero",1=>"one");
print_r(json_encode($array)); // output: {"0":"zero","2":"two"}
print_r(json_encode($another_array)); //output: ["zero","one"]
?>
so what's the reason for that ?
Because array(0=>"zero",1=>"one") is the same as array("zero", "one") and the JSON encoder assumes the latter is a list (since that's how PHP does lists) and has no way to tell the former from the latter.
If you want to force json_encode to treat all arrays as objects, pass JSON_FORCE_OBJECT as the second argument:
json_encode(array(0=>"zero",1=>"one"), JSON_FORCE_OBJECT)
// {"0":"zero","1":"one"}
If you always want a json list instead, get rid of the keys (e.g. using array_values()) before encoding.
Related
When using json_encode, it annoyingly automatically coverts the int keys to strings. For example, if you have an array:
$a = array();
$a[12] = 15;
echo json_encode($a);
{"12":15} //notice the quotes around 12
After searching SO, the solution is to use
json_encode($array,JSON_NUMERIC_CHECK)
However, that is only available in php > 5.3.3. The production server I'm stuck with is using 5.3.2.
Surely there is a work around?
So the problem here is that you are basically mixing your approach to the data structure and json_encode() is trying to make a best guess as to how to interpret your array, since in JSON, there is not such concept of a non-zero based, numerically indexed array.
If for example, you had a zero-based numeric array with a continuous number sequence, json_encode() would encode this a a numerically-indexed array of the format:
[value1, value2, ...]
Since you don't have a zero-based array, your data structure is being interpreted as an object structure and given a string key (the only available key type for an object in JSON) of the format:
{"key", value}
So it seems you need to make up your mind as to what you are really trying to represent in your array. Do you only need a numerically based array, or do you need object encoding.
I my php file, I need to make my own Json array.
for($i=1;$i<$arraySize+1;$i++){
$idJson[$i]=$i.":".$birdIDArray[$i-1];
}
for($i=$arraySize+1 ;$i<$arraySize*2+1; $i++){
$idJson[$i]=$i.":".$rankArray[$i-($arraySize+1)];
}
When I use
print(json_encode($idJson));
the OUTPUT : ["0:3","1:15","2:3","3:14","4:1","5:2","6:2"]
But i need the output like this ["0":"3","1":"15","2":"3","3":"14","4":"1","5":2","6":"2"]
When I going to add " mark
for($i=1;$i<$arraySize+1;$i++){
$idJson[$i]=$i.'"'.":".'"'.$birdIDArray[$i-1];
}
for($i=$arraySize+1 ;$i<$arraySize*2+1; $i++){
$idJson[$i]=$i.'"'.":".'"'.$rankArray[$i-($arraySize+1)];
}
It prints like this
["0:3","1\":\"15","2\":\"3","3\":\"14","4\":\"1","5\":\"2","6\":\"2"]
How can I avoid from printing this \ sign?
I'm assuming you want a JSON object like this:
{"0":"3", ... }
The problem here is that Javascript/JSON distinguishes between key-value pairs, which are objects, and numerically indexed lists, which are arrays, while PHP uses arrays for both these things. With json_encode it depends on whether the PHP array is a continuously numerically indexed array, in which case you get a JSON array, or anything else, in which case you get a JSON object.
What you want is to force a JSON object even for a continuously numerically indexed array. The first question here would be: why?! But if you're really sure you want that (again, why?!), there's the JSON_FORCE_OBJECT flag in PHP 5.3+:
echo json_encode(array("3", "15", "3"), JSON_FORCE_OBJECT);
// {"0":"3","1":"15","2":"3"}
But I'll say again that that's pretty pointless. If you use a regular array like ["3","15","3"], the keys to those elements are already implicitly 0, 1 and 2. There's no need to enforce them as object keys.
Is there a PHP function to encode a generic multidimensional array as a string and get it back as a multidimensional array?
I need it to store in mysql some data (a drupal computed field to be precise). The array contains just floats and strings.
serialize() and unserialize() do what you describe.
http://www.php.net/manual/en/function.serialize.php
http://www.php.net/manual/en/function.unserialize.php
You could also consider encoding the array as JSON with json_encode() and json_decode(), which gives more readable output, if that is important to you.
I second the use of "json_encode" and "json_decode". I believe the output of "json_encode" is less verbose than PHP's serialize function (since data types are inferred) and is immediately more portable (even though that is not a requirement).
Make sure you pass "TRUE" for the second parameter of "json_decode", otherwise you may get a simple object back, depending on how the original data was encoded.
So im trying to figure out the best way to get MySql table data into either a multidimensional PHP array or convert that multidimensional array into a json string.
Essentially what im trying to do is have a php include that returns the JSON string so i can iterate through it. I am needing a single key with multiple values, so im not 100% sure that im headed in the right direction.
I want to assign multiple values to the same key, for example:
[{"key1": "package1", "package2", "package3"}, {"key2": "package1", "package2", "package3", "package4"}]
I think that is not going to work right? Because i dont have any type of index's?
That is not valid JSON. The structure you are looking for would be something like:
[
{"key1": ["package1", "package2", "package3"]},
{"key2": ["package1", "package2", "package3", "package4"}]
^ An array as the value to the key "key1", "key2", etc..
]
At the PHP side, you would need something like:
For every row fetched from MySQL
$arr[$key] = <new array>
for each package:
append package to $arr[$key]
echo out json_encode($arr)
JS arrays have an implicit array keying, starting at index 0. What you've got is a perfectly valid JS array, the equivalent of having written:
var x = []; // create new empty array
x[0] = {"key1": .... }; // first object
x[1] = {"key2": ....} // second object
Note that the contents of your {} sub-objects is NOT valid.
You should never EVER built a JSON string by hand. It's too unreliable and easy to mess up. It's just easier to use a native data structure (php arrays/objects), then json_encode() them. Ditto on the other end of the process - don't decode the string manually. Convert to a native data structure (e.g. json_decode(), JSON.parse()) and then deal with the native structure directly.
essentially, JSON is a transmission format, not a manipulation format.
i have an simple array:
array
0 => string 'Kum' (length=3)
1 => string 'Kumpel' (length=6)
when I encode the array using json_encode(), i get following:
["Kum","Kumpel"]
My question is, what is the reason to get ["Kum","Kumpel"] instead of { "0" : "Kum", "1" : "Kumpel" }?
"{}" brackets specify an object and "[]" are used for arrays according to JSON specification. Arrays don't have enumeration, if you look at it from memory allocation perspective. It's just data followed by more data, objects from other hand have properties with names and the data is assigned to the properties, therefore to encode such object you must also pass the correct property names. But for array you don't need to specify the indexes, because they always will be 0..n, where n is the length of the array - 1, the only thing that matters is the order of data.
$array = array("a","b","c");
json_encode($array); // ["a","b","c"]
json_encode($array, JSON_FORCE_OBJECT); // {"0":"a", "1":"b","2":"c"}
The reason why JSON_FORCE_OBJECT foces it to use "0,1,2" is because to assign data to obeject you must assign it to a property, since no property names are given by developer (only the data) the encoder uses array indexes as property names, because those are the only names which would make sense.
Note: according to PHP manual the options parameters are only available from PHP 5.3.
For older PHP versions refer to chelmertz's answer for a way to make json_encode to use indexes.
As Gumbo said, on the JS-side it won't matter. To force PHP into it, try this:
$a = new stdClass();
$a->{0} = "Kum";
$a->{1} = "Kumpel";
echo json_encode($a);
Not that usable, I'd stick with the array notation.
Just cast as an object and it will work fine...the JSON_FORCE_OBJECT parameter does exactly the same thing.
json_encode((object)$array);
Don't forget to convert it back into a php array so you can access its values in php:
$array = (object)$array;
$array = (array)$array;
json_encode($array);
Since you’re having a PHP array with just numeric keys, there is no need to use a JavaScript object. But if you need one, try Maiku Mori’s suggestion.
I personally think this is a bug that needs to be fixed in PHP. JSON_FORCE_OBJECT is absolutely not an answer. If you try to do any sort of generic programming you get tripped up constantly. For example, the following is valid PHP:
array("0" => array(0,1,2,3), "1" => array(4,5,6,7));
And should be converted to
{"0": [0,1,2,3], "1": [4,5,6,7]}
Yet PHP expects me to either accept
[[0,1,2,3],[4,5,6,7]]
or
{"0":{"0":1,"1":1,"2":2,"3":3},"1":{"0":4,"1":5,"2":6,"3":7}}
Neither of which are right at all. How can I possibly decode an object like that? What possible reason is there to ever change something that is clearly using strings as indexes? It's like PHP was trying to be clever to help out idiotic people who can't differentiate strings from ints, but in the process messed up anyone legitimately using strings as indexes, regardless of what the value COULD be turned into.