1. 程式人生 > >python中字典,沒鍵加鍵,有鍵操作其鍵對應的值,的思想

python中字典,沒鍵加鍵,有鍵操作其鍵對應的值,的思想

cars = ['魯A32444', '魯B12333', '京B8989M', '黑C49678', '黑C46555', '滬B25041', '黑C34567']
locations = {'': '上海', '': '北京', '': '黑龍江', '': '山東', '': '湖北', '': '湖南'}
# 構建此資料型別{'山東': 2, '北京': 1, '黑龍江': 3, '上海': 1}

# 方法一
dic = {}
for i in cars:
    if locations[i[0]] in dic:
        dic[locations[i[0]]] 
+= 1 else: dic[locations[i[0]]] = 1 print(dic) # 方法二 dic = {} for i in cars: # get方法,如果有鍵返回該鍵對應的值,如果沒鍵,可以設定返回值 dic[locations[i[0]]] = dic.get(locations[i[0]], 0) + 1 print(dic)
list3 = [
    {"name": "a", "hobby": "抽菸"},
    {"name": "a", "hobby": "喝酒"},
    {"name": "a", "hobby
": "燙頭"}, {"name": "wu", "hobby": "喊麥"}, {"name": "wu", "hobby": "街舞"}, ] # 構建資料型別 list4 = [{"name": "a", "hobby_list": ["抽菸", "喝酒", "湯頭"]}] # 思想:如果沒鍵就新增鍵,如果有鍵就操作此鍵對應的值 # 方法一 list4 = [] for i in list3: # print(i) for j in list4: if i['name'] == j['name']: # i['name']='a' j['
hobby_list'].append(i['hobby']) break else: list4.append({'name': i['name'], 'hobby_list': [i['hobby']]}) print(list4)
li = [11, 22, 33, 44, 55, 77, 88, 99, 90]
# 構建資料型別{'key1': [11, 22, 33, 44, 55], 'key2': [77, 88, 99, 90]}
# key1對應的小於60的值,key2對應大於60的值
result = {}
for i in li:
    if i < 66:
        if 'key1' not in result:
            result['key1'] = []
        result['key1'].append(i)
    else:
        if 'key2' not in result:
            result['key2'] = []
        result['key2'].append(i)
print(result)