PHP Error Undefined Offset, SQL Export tool - php

Question

I keep getting the error:
PHP Notice: Undefined offset: 1 in /home/mydomain/mydomain.com/admin/model/tool/export_xls.php on line 150
I've looked at the other similar posts but none of those resolutions work on my code. I don't see any numbers related to the array, and I've double checked for missing closing } . I asked the code developer and all he did was get it to stop displaying the error, but it still shows up (several thousand times) in my error log. line 150 is the blank line above the code
"//Get all options values to each option"
Code:
public function get_all_options()
{
$this->load->model('catalog/option');
$all_options = $this->model_catalog_option->getOptions();
$options_final = array();
//Format options
foreach ($all_options as $key => $op) {
$options_final[$op['name'].'_'.$op['type']] = array(
'option_id' => $op['option_id'],
'option_name' => $op['name'],
'option_values' => array()
);
}
//Get all options values to each option
foreach ($options_final as $option_name => $op) {
$option_values = $this->model_catalog_option->getOptionValues($op['option_id']);
//Format option values
$option_values_final = array();
foreach ($option_values as $key => $op) {
$option_values_final[$op['name']] = $op['option_value_id'];
}
$options_final[$option_name]['option_values'] = $option_values_final;
}
return $options_final;
}

Answer 1

This is because you are accessing an array which index is not set . try something like this
//Format options
foreach ($all_options as $key => $op) {
$options_final[$op['name'].'_'.$op['type']]
= array(
'option_id' =>isset($op['option_id']) ?
:$op['option_id']:null,
'option_name' => isset($op['option_name'])
? :$op['option_name']:null,
'option_values' => array()
);
}