的Python追加在文件JSON对象，后卫如果对象不存在

Question

我读在一个JSON文件使用python，然后在对象内以阵列追加，这是

"additional_info": {"other_names": ["12.13"] 

我的形状追加数组如下：

data["additional_info"]["other_names"].append('13.9') 
with open('jsonfile', 'w') as f: 
    json.dump(data, f) 

我想设置一个后卫，以检查是否ADDITIONAL_INFO和other_names在JSON文件是否存在，如果没有的话创建它。我会如何去做这件事？

Answer 1

通常我会用嵌套try-except检查每个丢失钥匙或defaultdict，但在这种情况下，我想我会用2个if语句去为简单起见：

if "additional_info" not in data: 
    data["additional_info"] = {} 
if "other_names" not in data["additional_info"]: 
    data["additional_info"]["other_names"] = [] 

data["additional_info"]["other_names"].append('13.9') 

with open('jsonfile', 'w') as f: 
    json.dump(data, f) 

两个用例：

data = {} 

if "additional_info" not in data: 
    data["additional_info"] = {} 
if "other_names" not in data["additional_info"]: 
    data["additional_info"]["other_names"] = [] 

data["additional_info"]["other_names"].append('13.9') 

print(data) 
>> {'additional_info': {'other_names': ['13.9']}} 

而且

data = {"additional_info": {"other_names": ["12.13"]}} 

if "additional_info" not in data: 
    data["additional_info"] = {} 
if "other_names" not in data["additional_info"]: 
    data["additional_info"]["other_names"] = [] 

data["additional_info"]["other_names"].append('13.9') 

print(data) 
>> {'additional_info': {'other_names': ['12.13', '13.9']}}