在自循环函数php中查找父类别

Question

Find the top category in tree structure, i am using this

echo getTopCategory($category_id); exit; // returning empty value



function getTopCategory($catid) {

    $CI = & get_instance();
    $CI->db->select('*');
    $CI->db->from('categories');
    $CI->db->where('id', $catid);
    $query = $CI->db->get();
    $result = $query->row();
    //return $catid; // for testing return working
    if($result->parent_id==0){
        //echo $catid -- working result 350
        return $catid; // root parent, not successfully returning the result
    }else{
        getTopCategory($result->parent_id);
    }

}

if i use echo inside the getTopCategory($catid) it correctly giving the parent category id but it not returning date to getTopCategory($category_id);

Answer 1

Return it then, see my comment in the code:

echo getTopCategory($category_id); exit; // returning empty value



function getTopCategory($catid) {

    $CI = & get_instance();
    $CI->db->select('*');
    $CI->db->from('categories');
    $CI->db->where('id', $catid);
    $query = $CI->db->get();
    $result = $query->row();
    //return $catid; // for testing return working
    if($result->parent_id==0){
        //echo $catid -- working result 350
        return $catid; // root parent 
    }else{
        //Ive added a return here
        return getTopCategory($result->parent_id);
    }

}

When you do a recursive call, you need to return the value from the recursive call itself, so it can bubble all the way back to your echo command.