Undefined index when saved to options
$options = get_option('analytics');
if ( ! preg_match( '/^([0-9]{4})-([0-9]{2})-([0-9]{2})$/', $options['analytics_startdate'] ) ) {
$options['analytics_startdate'] = '2018-12-01';
}
Why this is throwing an error :
Undefined index: analytics_startdate ,
though i am specifying it.