PHP - Undefined offset (0) even though it holds a value - php

Question

I'm trying to work in a CodeIgniter environment and while trying to collect and gather some information into variables I'm getting some PHP NOTICE errors that don't seem right.
Here's the chunk of code where the error(s) occur:
if (empty($events['user'][$user_id])) {
unset($events['user'][$user_id]);
} else {
foreach ($events['user'][$user_id] as $event) {
$events['user'][$user_id]['events']['event_id'] = $event_id = $event['event_id'];
$events['user'][$user_id]['event']['date'] = $this->events_model->getEventDates($event_id);
$events['user'][$user_id]['event']['date'] = $events['user'][$user_id]['event']['date'][0]['date'];
$events['user'][$user_id]['event']['request_title'] = $event['request_title'];
$events['user'][$user_id]['event']['event_status_text'][] = $this->events_model->getEventStatusFromSectionStatuses($event_id);
$request_data = $this->requests_model->getRequestInfo($event['request_id']);
$events['user'][$user_id]['event']['ministry'] = $this->ministries_model->getMinistryTitle($request_data[0]['requesting_ministry']);
// more stuff will go here...
}
$content_data['event_status_text'] = $events['user'][$user_id]['event_status_text'];
$content_data['events'] = $events['user'][$user_id]['complete_events'];
$content_data['totals'] = $events['user'][$user_id]['totals'];
$content_data['updated_events'] = $events['user'][$user_id]['updated_events'];
}
The specific line of the first error is the third line inside the foreach loop that ends with ['date'][0]['date']. It's the [0] that PHP is telling me is undefined. However, if I echo that exact same variable like this:
echo $events['user'][$user_id]['event']['date'][0]['date'];
...it outputs a value as would be expected, which also tells me that the [0] is NOT undefined after all. I'm not actually changing the variable. The only difference is that I'm echoing it instead of assigning it to another variable.
If I use # to ignore it in here, it happens again a few lines later on the line ending with getMinistryTitle($request_data[0]['requesting_ministry']).
Can you see what I'm doing wrong? Let me know if you need to see more of the code.
Here's the getEventDates() code as requested (note this is not my code):
function getEventDates($event_id)
{
$sql = "SELECT date FROM `event_dates` WHERE event_id=? ORDER BY date";
$res = $this->db->query($sql, array($event_id));
return $res->result_array();
}
if I print out $this->events_model->getEventDates($event_id) I get the following:
Array
(
[0] => Array
(
[date] => 2014-05-01
)
[1] => Array
(
[date] => 2014-05-08
)
[2] => Array
(
[date] => 2014-05-15
)
[3] => Array
(
[date] => 2014-05-22
)
[4] => Array
(
[date] => 2014-05-29
)
[5] => Array
(
[date] => 2014-06-05
)
[6] => Array
(
[date] => 2014-06-12
)
)
Hmmm... is it possible that this error is happening because there isn't a direct value contained in [0], but rather another array level? Please note that I did not structure this output. Someone else coded this and it's just my job to come in and work with it.

Answer 1

Without seeing the rest of your code this is confusing:
$events['user'][$user_id]['event']['date'] = $this->events_model->getEventDates($event_id);
$events['user'][$user_id]['event']['date'] = $events['user'][$user_id]['event']['date'][0]['date'];
Why would you be setting $events['user'][$user_id]['event']['date'] in one line and then in the next overriding it again?
My best advice would be to set the first assignment in a variable independent of the array, and then calling that variable for the data:
$event_dates_temp = $this->events_model->getEventDates($event_id);
$events['user'][$user_id]['event']['date'] = $event_dates_temp[0];
And perhaps adding a conditional check to ensure you are setting things that exist:
$event_dates_temp = $this->events_model->getEventDates($event_id);
if (array_key_exists(0, $event_dates_temp)) {
$events['user'][$user_id]['event']['date'] = $event_dates_temp[0];
}
Also, it’s unclear at what point you are doing this:
echo $events['user'][$user_id]['event']['date'][0]['date'];
And what is the output when you do dump like this:
echo '<pre>';
print_r($events['user'][$user_id]['event']['date']);
echo '</pre>';

Answer 2

It happens when you are trying to access a value which is not set for that index, please read this link for more information.
There are two options available:
Ignore these notices by telling the PHP error_reporting to not show notices error_reporting(E_ALL ^ E_NOTICE); but it is a good practice to fix this error by adding a check if a value exists.
Fix the values by isset function to see if the value/index contains any data.

Answer 3

If You hide notice set error_reporting(E_ALL ^ E_NOTICE);
Solution is use isset() to solved this issue.