Question

given

[
  ('object-top-1','object-lvl1-1','object-lvl2-1'),
  ('object-top-2','object-lvl1-1','object-lvl2-2','object-lvl3-1')
  ('object-top-1','object-lvl1-1','object-lvl2-3'),
  ('object-top-2','object-lvl1-2','object-lvl2-4','object-lvl3-2','object-lvl4-1'),
]

and so on .. where all the tuples are of arbitrary length

Any way to efficiently convert them to

{'object-top-1': {
      'object-lvl1-1': {
                   'object-lvl2-1': {},
                   'object-lvl2-3':{}
                }
       },
 'object-top-2': {
       'object-lvl1-1':{
                'object-lvl2-2': { 
                     'object-lvl3-1' : {} 
                     }
                 }
       }
       'object-lvl1-2':{
                'object-lvl2-4': {
                         'object-lvl3-2' : { 
                              'object-lvl4-1': {}
                         }
                 }
        }
 }

I’ve been stuck trying to figure this out for quite some time now >.<

Thanks!

Answer 1

def treeify(seq):
    ret = {}
    for path in seq:
        cur = ret
        for node in path:
            cur = cur.setdefault(node, {})
    return ret

Example:

>>> pprint.pprint(treeify(L))
{'object-top-1': {'object-lvl1-1': {'object-lvl2-1': {}, 'object-lvl2-3': {}}},
 'object-top-2': {'object-lvl1-1': {'object-lvl2-2': {'object-lvl3-1': {}}},
                  'object-lvl1-2': {'object-lvl2-4': {'object-lvl3-2': {'object-lvl4-1': {}}}}}}

dict.setdefault is an underappreciated method.