PHP - get JSON parent value

Question

In php, I'm trying to get the numbers (0, 13, 20, 45, 53, 56) from this json file:

{
    "0": {
        "classcat": "a",
    },
    "13": {
        "classcat": "b",
    },
    "20": {
        "classcat": "c",
    },
    "45": {
        "classcat": "d",
    },
    "53": {
        "classcat": "e",
    },
}

Im populating this file to a selectfield with a foreach loop. My desired output would be:

<select>
<option value="(classcatvalue)">(classcatvalue + number)</option>
<option value="a">a 0</option>
<option value="b">b 13</option>
<option value="c">c 20</option>
<option value="d">d 45</option>
<option value="e">e 53</option>
</select>

Looks simple, but i cannot figure it out. Any ideas?

http://php.net/manual/en/function.json-decode.php http://php.net/manual/en/control-structures.foreach.php — Sammitch, Dec 18 '17 at 21:19
Why all the downvotes? Trying to make it simple, and with code examples, and still... — stangerup, Dec 19 '17 at 09:20
@stangerup There is no PHP code in your question, which is the main subject itself. Anyway, you probably got the downvotes for not showing enough research since JSON parsing with PHP is a pretty common topic and a simple search for example could have solved this for you. And also, your JSON is invalid. Answers like the accepted one will only work if you make it valid... — sidyll, Dec 19 '17 at 14:24

score 0 · Answer 1 · answered Dec 18 '17 at 21:43

One main problem is that your JSON is not valid. You have a lot of extra commas. After fixing that, you can transform it into an associative array with json_decode():

$options = json_decode(<<<JSON
{
    "0" : { "classcat": "a" },
    "13": { "classcat": "b" },
    "20": { "classcat": "c" },
    "45": { "classcat": "d" },
    "53": { "classcat": "e" }
}
JSON
, true);

And optionally simplify the values, removing the inner object/array and writing the values themselves:

array_walk($options, function(&$v, $k) { $v = $v['classcat']; });

Now it's just a matter of using a foreach loop to output your options:

<select>
  <option value="(classcatvalue)">(classcatvalue + number)</option>
<?php foreach ($options as $n => $cat) : ?>
  <option value="<?= $cat ?>"><?= "$cat $n" ?></option>
<?php endforeach; ?>
</select>

Hadn't the values been simplified, one ought to use $cat['classcat'] instead.

score 0 · Accepted Answer · answered Dec 18 '17 at 21:59

0

Use json_decode() to convert the JSON to a PHP array, then use foreach to loop over it.

$array = json_decode($json, true);
foreach ($array as $number => $value) {
    $classcatvalue = $value['classcat'];
    echo "<option value="$classcatvalue">$number $classcatvalue</option>";
}

answered Dec 18 '17 at 21:59

Barmar

741,623
53
500
612

So simple. It works! Thank you. – stangerup Dec 19 '17 at 09:18

score -2 · Answer 3 · answered Dec 18 '17 at 21:20

-2

Use array_keys after you json_decoded the string.

$values = array_keys(json_decode($json_str, true));

// Now you can output them like:
Echo $values[1]; // 13

answered Dec 18 '17 at 21:20

Andreas

23,610
6
30
62

Anyone who can comment on why the downvote? – Andreas Dec 19 '17 at 06:55

PHP - get JSON parent value

3 Answers3