dictsのリストをグループ化するには？

Question

私はこれは私が何をしたかである私は、この（所望の出力を）好きにそれを変換したいdicts

[ 
    {"day":"10", "car":"bmw", "count":"3"}, 
    {"day":"10", "car":"audi", "count":"2"}, 
    {"day":"10", "car":"jeep", "count":"4"}, 
    {"day":"11", "car":"bmw", "count":"6"}, 
    {"day":"11", "car":"audi", "count":"7"}, 
    {"day":"11", "car":"jeep", "count":"8"}, 
] 

のリスト

[ 
     {"day":"10", "bmw":"3","audi":"2","jeep":"4"}, 
     {"day":"11","bmw":"6","audi":"7","jeep":"8"}, 
] 

を持っています。これを達成するためのより良い最適な方法があります。

def dl(): 
    list_of_dicts = [ 
      {"day":"10", "car":"bmw", "count":"3"}, 
      {"day":"10", "car":"audi", "count":"2"}, 
      {"day":"10", "car":"jeep", "count":"4"}, 
      {"day":"11", "car":"bmw", "count":"6"}, 
      {"day":"11", "car":"audi", "count":"7"}, 
      {"day":"11", "car":"jeep", "count":"8"}, 
      ] 

    result = [] 
    data = {} 

    for item in list_of_dicts: 

     if not data.get(item["day"], False):  
      data[item["day"]] = [] 
      data[item["day"]].append({item["car"]:item["count"]}) 

     else: 
      data[item["day"]].append({item["car"]:item["count"]}) 

    for key in data: 
     new_dict = {} 
     new_dict["day"] = key 
     for item in data[key]: 
      new_dict.update(item) 
     result.append(new_dict) 

    print result 
    return result 

dl() 

質問は正しい誰かがいない場合は、正しい

この質問に私を助けてください。私は、日ごとに新しい辞書を作成し、その日に基づいてグループに初心者

Answer 1

使用itertools.groupby午前：

list_of_dicts = [ 
    {"day":"10", "car":"bmw", "count":"3"}, 
    {"day":"10", "car":"audi", "count":"2"}, 
    {"day":"10", "car":"jeep", "count":"4"}, 
    {"day":"11", "car":"bmw", "count":"6"}, 
    {"day":"11", "car":"audi", "count":"7"}, 
    {"day":"11", "car":"jeep", "count":"8"}, 
] 

# to use groupby the list must be sorted 
list_of_dicts.sort(key=operator.itemgetter("day")) 

result_list = [] 
for day, dicts_for_that_day in itertools.groupby(list_of_dicts, key=operator.itemgetter("day")): 
    day_dict = {'day': day} 
    day_dict.update({d['car']: d['count'] for d in dicts_for_that_day}) 
    result_list.append(day_dict) 

print(result_list)