Python將json對象附加到文件中，如果對象不存在，則進行保護

Question

我正在使用python讀取json文件，然后在對象內添加數組，其形狀為

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

我將數組追加如下：

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

我想設置一個保護措施，以檢查json文件中是否存在extra_info和other_names，如果不存在則創建它。 我將如何去做呢？

Answer 1

通常，我會使用嵌套的try-except檢查每個丟失的鍵或defaultdict ，但是在這種情況下，為簡單起見，我認為我會使用2 if語句：

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)

兩個用例：

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']}}

和

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']}}