python之使用python编写json文件

我正在尝试使用 python 脚本读取和写入 json 文件(我已将此 python block 嵌入到 shell 脚本中)

测试.json

{ 
  "environments": ["dev", "qa", "load", "prod"], 
  "region": ["asia", "europe", "americas", "asia-pacific"], 
  "product": ["mobile", "internet", "kiosk", "branch"], 
  "ID": ["mobile:111", "internet:222", "kiosk:333", "branch:444"] 
} 

我正在尝试添加地区(英国)，在此之前我想检查并添加它是否在列表中不可用。 下面是我的 python 代码，我可以更新值

reg_val="uk" 
 
a_dict = {} 
try: 
    with open('test.json') as data_file: 
        data = json.load(data_file) 
        temp_list = [] 
        for dicObj in data["region"]: 
            temp_list.append(dicObj) 
        temp_list.append(reg_val) 
        data["region"] = temp_list 
        a_dict["region"] = data["region"] 
        with open('test.json','w') as f: 
            f.write(json.dumps(a_dict, indent=4, sort_keys=True, encoding="utf-8")) 
except IOError as io: 
    print "ERROR: ", io 

我能够更新 json 文件，但它删除了其他列表。我看到的输出是

{ 
    "region": [ 
        "asia",  
        "europe",  
        "americas",  
        "asia-pacific",  
        "uk" 
    ] 
}