There's no difference between quoted and unquoted keys. The problem is with the quoting around the actual data values, since Flot requires numbers, not strings.

The json_encode function decides to whether to quote based on the type of data you're giving it. In this case it looks like whatever operations you're performing to create $data are producing string values instead of integers. You need to re-examine those operations, or explicitly tell PHP to interpret them as numbers, using (int) or (float) casting, or the intval/floatval functions.

If you add an underscore to your regex at the end it will do it.

$array_final = preg_replace('/"([a-zA-Z]+[a-zA-Z0-9_]*)":/','array_final);

I assume that's what that preg_replace is for anyway.

It works but abit tricky way...

$.each(layer.data.features, function(index, polygons) { var coordinates = JSON.parse(polygons.geometry.coordinates); var values = []; var coord = []; for(var i = 0, l = coordinates.length; i < l; i++) { values.push(coordinates[i]); }
coord.push(values); var campus = { 'type': 'Feature', 'properties': { 'name': polygons.properties.name, 'category': polygons.properties.category, 'description': polygons.properties.description, 'style': { weight: 2, color: polygons.properties.style.color, opacity: 1, fillColor: polygons.properties.style.color, fillOpacity: 0.4 }}, 'geometry': { 'type': 'Polygon', 'coordinates': coord } };

                            var poly  = L.geoJson(campus,  {
                                                        style: function (feature) {
                                                            return feature.properties && feature.properties.style;
                                                        },
                                                        onEachFeature: onEachPolygonFeature,

                            });
                            map.addLayer(poly); 

                        });

Bill's function almost worked, it just needed the is_assoc() function added.

But while I was sorting this out, I cleaned it up a bit. This seems to work quite well for me:

<?php

/**
 * JSObject class.
 */

class JSObject {
    var $jsexp = 'JSEXP:';

    /**
     * is_assoc function.
     *
     * Determines whether or not the object is an associative array
     * 
     * @access public
     * @param mixed $arr
     * @return boolean
     */
    function is_assoc($arr) {
        return (is_array($arr) && count(array_filter(array_keys($arr),'is_string')) == count($arr));
    }

    /**
     * Encode object
     *
     * Encodes the object as a json string, parsing out items that were flagged as objects so that they are not wrapped in double quotes.
     *
     * @param     array   $properties
     * @return    string
     */
    function encode($properties = array()) {

        $is_assoc = $this->is_assoc($properties);

        $enc_left  = $is_assoc ? '{' : '[';
        $enc_right = $is_assoc ? '}' : ']';

        $outputArray = array();

        foreach ($properties as $prop => $value) {

            if ((is_array($value) && !empty($value)) || (is_string($value) && strlen(trim(str_replace($this->jsexp, '', $value))) > 0) || is_int($value) || is_float($value) || is_bool($value)) {

                $output = (is_string($prop)) ? $prop.': ' : '';

                if (is_array($value)) {
                    $output .= $this->encode($value);
                }
                else if (is_string($value)) {
                    $output .= (substr($value, 0, strlen($this->jsexp)) == $this->jsexp) ?  substr($value, strlen($this->jsexp))  : json_encode($value);
                }
                else {
                    $output .= json_encode($value);
                }


                $outputArray[] = $output;
            }
        }

        $fullOutput = implode(', ', $outputArray);

        return $enc_left . $fullOutput . $enc_right;
    }

    /**
     * JS expression
     *
     * Prefixes a string with the JS expression flag
     * Strings with this flag will not be quoted by encode() so they are evaluated as expressions
     *
     * @param   string  $str
     * @return  string
     */
    function js($str) {
        return $this->jsexp.$str;
    }
}

If you can't turn that into valid JSON at the source, then you can use Services_JSON from PEAR to parse it, since adding quotes around the key is a non-trivial error-prone process.

Services_JSON will correctly parse the invalid key string.

Example:

$json = new Services_JSON();
var_dump($json->decode('{key:"value"}'));

Output:

object(stdClass)#2 (1) {
  ["key"]=>
  string(5) "value"
}

You can use preg_replace

$a = array( 'a' => 'apple' , 'b' => 'banana' , 'c' => 'orange' );
$a = json_encode($a);

$yourJSON = own_format($a);

print_r($yourJSON); 
//{a:'apple',b:'banana'}

function own_format($jsonData){
    
    $pattern = array('/{"/i','/":/i','/,"/i');

    $preg = preg_replace($pattern[0], "{", $jsonData);
    $preg = preg_replace($pattern[1], ":", $preg);
    $preg = preg_replace($pattern[2], ",", $preg);
    
    $Output = str_replace('"',"'",$preg);
    
    return $Output;
}

If you want to convert your JSON to print a javascript object (that was my case) you can use ugly regex like this:

$myJsonString = preg_replace('/"([^"]+)"\s*:\s*/', '$1:', $myJsonString);

Source: https://hdtuto.com/article/php-how-to-remove-double-quotes-from-json-array-keys