未定义的偏移量提取数组时注意

When I run this code, it works, but it gives me NOTICE 'Undefined offset 1'. Can someone tell me how can I fix this? $this->_data is a multidimensional array.

foreach ($this->_data as $key => $values) {
    $this->_param[] = explode(",", $values[1]);
}

You need to check if there is any data in $values[1]

Use this:

foreach ($this->_data as $key => $values) {
    if (isset($values[1]){
       $this->_param[] = explode(",", $values[1]);
    }
}