how to validate a json empty object in php - php

Question

my php code works fine when it returns the result like this ->
{
"id": 267935,
"results": [
{
"key": "rc94yWXcyr0",
"name": "Trailer 1",
"site": "YouTube"
},
{
"key": "GZ0Bey4YUGI",
"name": "Official Trailer",
"site": "YouTube"
},
{
"key": "y1fZg0hhBX8",
"name": "Official Trailer 2",
"site": "YouTube"
}
]
}
but i get error
(Notice: Undefined variable: finaltrailers in ... )
when results return like this -->
{
"id": 392344,
"results": [
]
}
and this is my php code -->
$trailer = $json2['results'];
foreach($trailer as $trailers=>$keytrailers){
foreach($keytrailers as $alltrailers=>$allkeytrailers){
if($alltrailers == 'key'){
# $finaltrailers .= $allkeytrailers.',';
}
}
}
echo trim($finaltrailers,",");
how can i validate the empty array and give and error my self ? please help me thank you.

Answer 1

You have to define the variable to use it in trim.
Just add it at the beginning of your code.
$finaltrailers = '';
$trailer = $json2['results'];
foreach($trailer as $trailers=>$keytrailers){
foreach($keytrailers as $alltrailers=>$allkeytrailers){
if($alltrailers == 'key'){
# $finaltrailers .= $allkeytrailers.',';
}
}
}
echo trim($finaltrailers,",");