PHP foreach json_encode issues - php

Question

I got problems with json_encode.
My code below:
$jsonfiles = array('http://example.com/myjsonishere.php'); //Here's my JSON
foreach ( $jsonfiles as $jsonfile ) {
//read the json file contents
$jsondata = file_get_contents($jsonfile);
//convert json object to php associative array
$data = json_decode($jsondata, true);
$json = json_decode(stripslashes($data));
foreach ((array)$json as $u => $z){
foreach ($z as $n => $line){
//get the tweet details
$grap_item1 = $line['grap1'];
$grap_item2 = $line['grap2'];
$grap_item3 = $line['grap3'];
// execute this insertion
mysqli_stmt_execute($stmt);
}
}
}
Without that stripslashes, json_last_error would show error number 4 but now it's 0, so I'm good to go.
Without (array) in first foreach PHP error pop up:
Invalid foreach argument
Even if I have tested after $json = json_decode(stripslashes($data)); line : if(is_array($json)) the test is TRUE but still the foreach will not work without (array)
Anyway, in theory, my code passes the first foreach, but if I put inside first foreach loop e.g. var_dumb($z) or whatever, it will not print anything. So I guess my code is stuck in the first foreach.
Please, let me know if I could provide more information.