一行python实现树形结构的方法

def tree(): return defaultdict(tree)

users = tree()
users['harold']['username'] = 'bell'
users['handler']['username'] = 'master'

{'harold': {'username': 'bell'}, 'handler': {'username': 'master'}}

taxonomy= tree()
taxonomy['Animalia']['Chordata']['Mammalia']['Carnivora']['Felidae']['Felis']['cat']
taxonomy['Animalia']['Chordata']['Mammalia']['Carnivora']['Felidae']['Panthera']['lion']
taxonomy['Animalia']['Chordata']['Mammalia']['Carnivora']['Canidae']['Canis']['dog']
taxonomy['Animalia']['Chordata']['Mammalia']['Carnivora']['Canidae']['Canis']['coyote']
taxonomy['Plantae']['Solanales']['Solanaceae']['Solanum']['tomato']
taxonomy['Plantae']['Solanales']['Solanaceae']['Solanum']['potato']
taxonomy['Plantae']['Solanales']['Convolvulaceae']['Ipomoea']['sweet potato']

def dicts(t): return {k: dicts(t[k]) for k in t}

add(taxonomy, 'Animalia,Chordata,Mammalia,Cetacea,Balaenopteridae,Balaenoptera,blue whale'.split(','))

def add(t, keys):
  for key in keys:
    t = t[key]