recursively iterate nested python dictionary

Question

I have nested python dictionary like this.

d = {}
d[a] = b
d[c] = {1:2, 2:3}

I am trying to recursively convert the nested dictionary into an xml format since there can be more nested dictionary inside such as d[e] = {1:{2:3}, 3:4} . My desired XML format is like this

<root>
  <a>b</a>
  <c>
    <1>2</1> 
    <2>3</3>
  </c> 
</root>

I have so far this python code to handle nested xml using lxml library. But it doesn't give me the desired output.

def encode(node, Dict):  
  if len(Dict) == 0:  
    return node 
  for kee, val in Dict.items():  
    subNode = etree.SubElement(node, kee) 
    del msgDict[kee]  
    if not isinstance(val, dict): 
      subNode.text = str(val) 
    else: 
      return encode(subNode, val)

Any help is appreciated. Thank you.

Answer 1

The way you recall encode does not look correct. Maybe this helps. For simplicity I just append stuff to a list (called l ). Instead, you should do your etree.SubElement(...) .

def encode(D, l=[]):
    for k, v in D.items():
        if isinstance(v, dict):
            l2 = [k]
            encode(v, l2)
            l.append(l2)
        else:
            l.append([k, v])

Answer 2

I found the bug in my code, which is I didn't return the recursive call back to the original loop. After going inside nested elements, it "returns" and doesn't get back to original loop. Instead of return encode(subNode, val) , saving in a variable element = encode(subNode, val) solves the problem.