How to remove leading zeros from array keys
You can do this (note the cast to int):
foreach ($query->result() as $row) { $cal_data[(int)substr($row->date,8,2)] = $row->data;}
I'm guessing since you have substr(..., 8, 2) I assume it's a full date like 2017-07-30 or something like it.
So that means you can use date() to manipulate the data.
$cal_data[date("j", $row->date)] = $row->data;Date("j") is day number without leading zeros.
http://php.net/manual/en/function.date.php