dictionary - convert a list of delimited strings to a tree/nested dict, using python -

i trying convert list of dot-separated strings, e.g.

['one.two.three.four', 'one.six.seven.eight', 'five.nine.ten', 'twelve.zero'] 

into tree (nested lists or dicts - easy walk through). real data happens have 1 4 dot-separated parts of different length , has 2200 records in total. actual goal fill in set of 4 qcombobox'es data, in manner 1st qcombobox filled first set items ['one', 'five', 'twelve'] (no duplicates). depending on chosen item, 2nd qcombobox filled related items: 'one' be: ['two', 'six'], , on, if there's nested level.

so far i've got working list -> nested dicts solution, it's horribly slow, since use regular dict(). , seem have trouble redesign defaultdict in way work out filling comboboxes properly.

my current code:

def list2tree(m):     tmp = {}     in range(len(m)):         if m.count('.') == 0:             return m         = m.split('.', 1)         try:             tmp[a[0]].append(list2tree(a[1]))         except (keyerror, attributeerror):             tmp[a[0]] = list2tree(a[1])     return tmp  main_dict = {} = 0 m in methods:     main_dict = list2tree(m)     += 1     if (i % 100) == 0: print i, len(methods) print main_dict, i, len(methods) 

ls = ['one.two.three.four', 'one.six.seven.eight', 'five.nine.ten', 'twelve.zero'] tree = {}  item in ls:     t = tree     part in item.split('.'):         t = t.setdefault(part, {}) 

result:

{  "twelve": {   "zero": {}  },   "five": {   "nine": {    "ten": {}   }  },   "one": {   "six": {    "seven": {     "eight": {}    }   },    "two": {    "three": {     "four": {}    }   }  } }