eerror message in php in codeigniter

eerror message in php in codeigniter

hi all in model i gave in function as follows
$query = $this->db->get();
$result = $query->result();
$data[] = $result;
but am getting error as A PHP Error was encountered
Severity: Notice
Message: Undefined variable: data
Filename: models/survey_model.php
Line Number: 845
null
what was the for this. can someone help me please