Automizing deeply nested function python

Question

I have a database model with deeply nested children. I am trying to add add all of the underlying ids (of all levels) to a dictionary entry. My current code looks as follows:

children = obj.children
    for child in children:
        data["children_ids"].append(child.id)
        for child in child.children:
            data["children_ids"].append(child.id)
            for child in child.children:
                data["children_ids"].append(child.id)
                for child in child.children:
                    data["children_ids"].append(child.id)

This code is fully functional, but the problem is fairly obvious. I don't want to keep writing the same code over and over again: it's ugly, impractical and not very maintainable. How would I do this?

Answer 1

Use a recursive function to run the same code on different children:

def add_children_ids(ids, children):
    for child in children:
        ids.append(child.id)
        add_children_ids(ids, child.children)

children = obj.children
data['children_ids'] = []
add_children_ids(data['children_ids'], children)

Because ids is a mutable list, there's no need to return it