如何在数组中生成一行 space

How to produce a line space in arrays

$arr = array(
   'toemail'=>$v->agent_primary_email,
   'agentname'=>$v->agent_firstname,
   'agentid'=>$v->agent_id,
   'subject'=>'The details of total number of properties saved by your clients',
   'totalprop'=>$v->prop_count
);
echo json_encode($arr);exit;

输出看起来像这样

{"toemail":"abc@gmail.com","agentname":"john","agentid":"110012","subject":"The    details of total number of properties saved by your clients","totalprop":"131"}

但是我应该进行哪些更改才能使输出看起来像这样

{"toemail":"abc@gmail.com",
 "agentname":"john",
 "agentid":"110012",
 "subject":"The details of total number of properties saved by your                     clients",
 "totalprop":"131"}

使用JSON_PRETTY_PRINT还需要使用echo "<pre>";

From PHP Manual: 在返回的数据中使用空格对其进行格式化。自 PHP 5.4.0

起可用
$array = array(
    'test'=>1,
    'test2'=>'test',
    'test3'=>'test 3'
);
echo "<pre>";
echo json_encode($array,JSON_PRETTY_PRINT);

结果:

{
    "test": 1,
    "test2": "test",
    "test3": "test 3"
}