Question

I’m just not a good enough computer scientist to figure this out by myself 🙁

I have an API that returns JSON responses that look like this:

// call to /api/get/200
{ id : 200, name : 'France', childNode: [ id: 400, id: 500] } 
// call to /api/get/400
{ id : 400, name : 'Paris', childNode: [ id: 882, id: 417] } 
// call to /api/get/500
{ id : 500, name : 'Lyon', childNode: [ id: 998, id: 104] } 
// etc

I would like to parse it recursively and build a hierarchical JSON object that looks something like this:

{ id: 200,
  name: 'France', 
  children: [
     { id: 400,
       name: 'Paris',
       children: [...]
     },
     { id: 500,
       name: 'Lyon', 
       children: [...]
     } 
  ],
} 

So far, I have this, which does parse every node of the tree, but doesn’t save it into a JSON object. How can I expand this to save it into the JSON object?

hierarchy = {}
def get_child_nodes(node_id):   
    request = urllib2.Request(ROOT_URL + node_id)
    response = json.loads(urllib2.urlopen(request).read())
    for childnode in response['childNode']:
        temp_obj = {}
        temp_obj['id'] = childnode['id']
        temp_obj['name'] = childnode['name']
        children = get_child_nodes(temp_obj['id'])
     // How to save temp_obj into the hierarchy?
get_child_nodes(ROOT_NODE)

This isn’t homework, but maybe I need to do some homework to get better at solving this kind of problem 🙁 Thank you for any help.

Answer 1

def get_node(node_id):   
    request = urllib2.Request(ROOT_URL + node_id)
    response = json.loads(urllib2.urlopen(request).read())
    temp_obj = {}
    temp_obj['id'] = response['id']
    temp_obj['name'] = response['name']
    temp_obj['children'] = [get_node(child['id']) for child in response['childNode']]
    return temp_obj

hierarchy = get_node(ROOT_NODE)