在字典列表中查找键值，然后替换其他值

Question

I'm using Python and a JSON file containing a list of dictionaries like so:

[
  {'name':'person1','id':'123','status':'absent'},
  {'name':'person2','id':'0980','status':'away'},
  {'name':'person3','id':'5235','status':'present'}
]

And I have an incoming dictionary with the same format:

{'name':'person1','id':'324','status':'present'}

The incoming dictionary can have one thing in common, and that's the name key, if the value for the 'name' key hasn't been seen, I add it the json file, if it has, I update the values for the id and status keys in the json file. I'm having trouble updating the list of dictionaries in the json file.

Taking the examples I gave above, the resulting json file should look like this:

[
  {'name':'person1','id':'324','status':'present'},
  {'name':'person2','id':'0980','status':'away'},
  {'name':'person3','id':'5235','status':'present'}
]

I can manage to find the dictionary I want to change with the following:

dict_to_update = next(item for item in <jsonfilename> if item['name'] == 'desired name')

After this, I'm stuck trying to figure out how to then update the specific dictionary in the json file. Any ideas? Thank you.

Answer 1

Here is how:

with open('file.json', 'r') as r:
    lst = json.load(r)

for i,d in enumerate(lst):
    if d['name'] == dct['name']:
        lst[i] = dct

with open('file.json', 'w') as f:
    json.dump(lst , f)

---

---

You can also use a function:

def update(lst):
    for i,d in enumerate(lst):
        if d['name'] == dct['name']:
            lst[i] = dct
    return lst

with open('file.json', 'r') as r:
    lst = update(json.load(r))

with open('file.json', 'w') as f:
    json.dump(lst , f)

Answer 2

list_of_dict = [
    {"name": "person1", "id": "123", "status": "absent"},
    {"name": "person2", "id": "0980", "status": "away"},
    {"name": "person3", "id": "5235", "status": "present"},
]

incoming_dictionary = {"name": "person1", "id": "324", "status": "present"}

for index, dictionary in enumerate(list_of_dict):
    if incoming_dictionary["name"] == dictionary["name"]:
        list_of_dict[
            index
        ] = incoming_dictionary  # replace the dictionary with the new one
        break
else:
    # if no match was found then append the incoming dictionary
    list_of_dict.append(incoming_dictionary)

Answer 3

Here's a function that does so, maybe not as elegantly as other answers:

def process(new_dict):
    global data  #jsonfilename
    if new_dict['name'] in [d['name'] for d in data]:
        data = [d for d in data if d['name'] != new_dict['name']]
    data.append(new_dict)
    data = sorted(data, key=lambda i: i['name'])

Full example:

data = [{'name':'person1','id':'123','status':'absent'},
        {'name':'person2','id':'0980','status':'away'},
        {'name':'person3','id':'5235','status':'present'}]

process({'name':'person1','id':'324','status':'present'})  #an overwritten person
process({'name':'person4','id':'324','status':'present'})  #a new person

Result:

[{'name': 'person1', 'id': '324', 'status': 'present'},
 {'name': 'person2', 'id': '0980', 'status': 'away'},
 {'name': 'person3', 'id': '5235', 'status': 'present'},
 {'name': 'person4', 'id': '324', 'status': 'present'}]

You can do this while avoiding the global keyword as well, but I thought this seemed alright for modifying an existing structure in place.

Answer 4

Maybe this can help you, and if you found another short solution please let me know. I make an iteration for the list of dictionary, and add a conditional to change the value of key id and status. Another way is we can use filter and map, to have a short code instead.

datas = [{'name': 'person1', 'id': '123', 'status': 'absent'}, {'name': 'person2', 'id': '0980',
                                                    'status': 'away'}, {'name': 'person3', 'id': '5235', 'status': 'present'}]
newData = {'name':'person1','id':'324','status':'present'}
for data in datas:
    if data["name"]==newData["name"]:
        data["id"]=newData["id"]
        data["status"]=newData["status"]