Flatten simple Python objects to a list of K-V pairs

flatten.py

'''
Flattens a 'JSON' object (really, a simple potentially nested object
composed of dicts, lists, and scalars) into a list of key-value pairs.

Example usage (from http://json.org/example.html):

  > import json
  > flatten_json(json.loads(SAMPLE_JSON))

  [(u'glossary.GlossDiv.GlossList.GlossEntry.GlossDef.GlossSeeAlso.0', u'GML'),
   (u'glossary.GlossDiv.GlossList.GlossEntry.GlossDef.GlossSeeAlso.1', u'XML'),
   (u'glossary.GlossDiv.GlossList.GlossEntry.GlossDef.para',
    u'A meta-markup language, used to create markup languages such as DocBook.'),
   (u'glossary.GlossDiv.GlossList.GlossEntry.GlossSee', u'markup'),
   (u'glossary.GlossDiv.GlossList.GlossEntry.Acronym', u'SGML'),
   (u'glossary.GlossDiv.GlossList.GlossEntry.GlossTerm',
    u'Standard Generalized Markup Language'),
   (u'glossary.GlossDiv.GlossList.GlossEntry.Abbrev', u'ISO 8879:1986'),
   (u'glossary.GlossDiv.GlossList.GlossEntry.SortAs', u'SGML'),
   (u'glossary.GlossDiv.GlossList.GlossEntry.ID', u'SGML'),
   (u'glossary.GlossDiv.title', u'S'),
   (u'glossary.title', u'example glossary')]

'''

SAMPLE_JSON = '''
{
  "glossary": {
    "title": "example glossary",
    "GlossDiv": {
      "title": "S",
      "GlossList": {
        "GlossEntry": {
          "ID": "SGML",
          "SortAs": "SGML",
          "GlossTerm": "Standard Generalized Markup Language",
          "Acronym": "SGML",
          "Abbrev": "ISO 8879:1986",
          "GlossDef": {
            "para": "A meta-markup language, used to create markup languages such as DocBook.",
            "GlossSeeAlso": [
              "GML",
              "XML"
            ]
          },
          "GlossSee": "markup"
        }
      }
    }
  }
}
'''


def join_paths(*args):
    return '.'.join([s.strip('.') for s in args if s])

def flatten_json(obj, path_so_far=None):
    if type(obj) == dict:
        results = []
        for k, v in obj.iteritems():
            results.extend(flatten_json(v, join_paths(path_so_far, k)))
        return results
    elif type(obj) == list:
        results = []
        for idx, v in enumerate(obj):
            results.extend(flatten_json(v, join_paths(path_so_far, str(idx))))
        return results
    else:
        return [(path_so_far, obj)]