append数据如何到python中的json文件？

Question

I have a json file with these data inside:

[
  {
    "t1": 62.000000,
    "t2": 26.200001,
    "Ir": 100
  },
  {
    "t1": 62.000000,
    "t2": 26.200001,
    "Ir": 100
  },
  {
    "t1": 63.000000,
    "t2": 26.200001,
    "Ir": 100
  }
]

Then on my python code, i read it with these command:

with open("data.json", 'r+') as file:
    old_data_list = json.load(file)

The type of old_data_list is <class 'list'>

So I want to append some data to this list. I receive the data from a ESP32 and then a read it with this command:

data = message.payload.decode('utf-8') # turn bytes to string

When i try to append the data to the json file, that's what i get:

[
  {
    "t1": 62.000000,
    "t2": 26.200001,
    "Ir": 100
  },
  {
    "t1": 62.000000,
    "t2": 26.200001,
    "Ir": 100
  },
  {
    "t1": 63.000000,
    "t2": 26.200001,
    "Ir": 100
  },"{"t1":64.000000,"t2":25.799999,"Ir":100}"
]

But what i want is:

[
  {
    "t1": 62.000000,
    "t2": 26.200001,
    "Ir": 100
  },
  {
    "t1": 62.000000,
    "t2": 26.200001,
    "Ir": 100
  },
  {
    "t1": 63.000000,
    "t2": 26.200001,
    "Ir": 100
  },
  {
    "t1": 64.000000,
    "t2": 25.799999,
    "Ir": 100
  },
]

Answer 1

Python does the right thing as data is a string, not a dictionary. Try:

data = json.loads(message.payload.decode('utf-8'))