PHP中数组转json格式

//对$data进行json编码，返回json对象的数组
function jsonEncode($data){
$jsonarr = '';
foreach($data as $value){
$jsondata = json_encode($value);
$jsonarr =$jsonarr.",".$jsondata ;
}
$jsonarr = ltrim($jsonarr,',');
$jsonarr = '['.$jsonarr.']';
return $jsonarr;
}