Return valid Json array - php

Question

I'm fairly new to Json and arrays and I'm just wondering whether someone can correct the code I've tried that is still outputting an invalid string.
$json = array(
'posts' => array(),
);
while($row = mysqli_fetch_array($result)) {
$posts = array();
$posts['count'] = $rowcount;
$posts['streamitem_id'] = $row['streamitem_id'];
$json['posts'] = $posts;
echo json_encode($json);
}
I have used http://jsonlint.com/ and posted my returned data from firebug errors on lines 6,11 and 16
} {
{
"posts": {
"count": 4,
"streamitem_id": "1976"
}
} {
"posts": {
"count": 4,
"streamitem_id": "1980"
}
} {
"posts": {
"count": 4,
"streamitem_id": "1099"
}
} {
"posts": {
"count": 4,
"streamitem_id": "1178"
}
}

Answer 1

Some have already commented with a valid answer however, I believe array_push is the most efficient method rather than redefining the $posts variable over and over.
$json = array(
'posts' => array()
);
while($row = mysqli_fetch_array($result)) {
array_push($json['posts'], $array(
'count' => $rowcount,
'streamitem_id' => $row['streamitem_id']
)
);
}
echo json_encode($json);
PS: I noticed that you're putting $rowcount in each post array. If this is not intended, I recommend the following change:
$json = array(
'posts' => array(),
'count' => $rowcount
);
And then in the while loop:
array_push($json['posts'], $array(
'streamitem_id' => $row['streamitem_id']
)
);
This way, you can reference the post count and it won't be a waste of memory.
console.log(json['count']);

Answer 2

I think you want this:
$posts = array();
$rowcount = 0;
while ($row = mysqli_fetch_array($result)) {
$posts[] = array(
'count' => $rowcount,
'streamitem_id' = $row['streamitem_id'],
);
$rowcount++;
}
$json['posts'] = $posts;
echo json_encode($json);

Answer 3

Put this outside of loop, you are overwriting and echoing each value instead whole at once
Inside loop
$posts[] = ["count"=> $rowcount,"streamitem_id"=>$row['streamitem_id']);
After loop
$json['posts'] = $posts;
echo json_encode($json);