{'user1':0.456,'user2':0.999,'user3':0.789,user:'0.234'}

def order_dict(dicts, n):
 result = []
 result1 = []
 p = sorted([(k, v) for k, v in dicts.items()], reverse=True)
 s = set()
 for i in p:
  s.add(i[1])
 for i in sorted(s, reverse=True)[:n]:
  for j in p:
   if j[1] == i:
    result.append(j)
 for r in result:
  result1.append(r[0])
 return result1

dic = {‘user1':'01', ‘user2':'02'} 

list(dic.keys())[list(dic.values()).index('01')]

d = {1:1, 2:0, 3:2}
min(d, key=d.get) //最小 
max(d, key=d.get) //最大

min(d.items(), key=lambda x: x[1]) 
min(d, key=lambda x: d[x])