Remove double quote in json_encode()

I want remove double quote in my json_encode, that is my code:

<?php

require_once 'config.inc.php';
//## Clase Base de Datos
require_once 'Database.class.php';
//## Obtengo los parametros pasados por el metodo GET
$params = $_REQUEST;

$db = new Database(DB_SERVER, DB_USER, DB_PASS, DB_DATABASE);
$db->connect();

$result = mysql_query("SELECT * from ranking WHERE posicion BETWEEN     ".$params['pos_ini']." AND ".$params['pos_fi']) or die('Could not query');

if(mysql_num_rows($result)){
    $array_json=array();
    $filas = mysql_num_rows($result);
    $columnas = mysql_num_fields($result);

    for($i=0;$i<$filas;$i++)
    {
        $fila_dato = mysql_fetch_assoc($result);
        for($k=0;$k<$columnas;$k++)
        {
                    $campo = mysql_field_name($result,$k);
                    $campo = str_replace('"', '', $campo);
                    $array_json[$i][$campo] = $fila_dato[$campo];
        }
    }
    $array_final = json_encode($array_json);
    $array_final = preg_replace('/"([a-zA-Z]+[a-zA-Z0-9]*)":/','$1:',$array_final);
    echo $array_final;
} else {
    echo '[]';
}
?>

My result is that:

[{"id_posiciones":"1",posicion:"1",nick:"biwer",puntos:"1000",uid:"1",pais:"ES",idioma:"ES","device_version":"4"}]

I want to remove double quote of “id_posiciones” and “device_version” too.

How can I do for the result is that:

[{id_posiciones:"1",posicion:"1",nick:"biwer",puntos:"1000",uid:"1",pais:"ES",idioma:"ES",device_version:"4"}]

Answer

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_]*)":/','$1:',$array_final);

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