How to attach an element in a list and write it to JSON?

Question

1. Load JSON file to aPool list at beginning.

   def LoadPoolTemplate():
     sFilename = './pool_template.json'
   
     if os.path.exists(sFilename):
       with open(sFilename, 'r') as fJsonFile:
         aPool = json.load(fJsonFile)
   
     return aPool
   

2. Append aTempJson to aPool[index]['devices']

   def UpdateJSON(aPool, aDevList):
     sFilename = './device_template.json'
     if os.path.exists(sFilename):
       with open(sFilename, 'r') as fJsonFile:
         aTempJson = json.load(fJsonFile)
     else:
       print ("No such file names " + sFilename)
   
     for item in aDevList:
       aTempJson['id'] = item[1]
       aTempJson['atti']['high'] = item[2]
   
       for (i,pid) in enumerate(aPool):
         if pid['id'] == item[0]:
           aPool[i]['devices'].append(aTempJson)
           break
   

3. Update aPool list to JSON file

   def CreateDeviceJSON(aDevice):
     with open(gDevice, 'w') as fOutfile:
       json.dump(aDevice, fOutfile, indent=2)
   

4. Read list

   def ReadDeviceList():
     aDevList = []
   
     with open(gDevList, 'r') as fList:
       for line in fList:
         columns = line.strip().split(',')
         aDevList.append(columns)
   
     return aDevList
   

5. main function

   def main():
     aDevDist = []
     aDeviceJson = []
   
     aDeviceJson = LoadPoolTemplate()
     aDeviceList = ReadDeviceList()
     aDeviceJson = UpdateJSON(aDeviceJson, aDeviceList)
   
     CreateDeviceJSON(aDeviceJson)
   

I don't know why all the elements in devices list are the same, please help me.

JSON file output:

[
  {
    "id": "id1",
    "devices": [
      {
         "atti": {
          "high": "190",
          "weight": "80"
        },
        "id": "Jordan"
      },
      {
         "atti": {
          "high": "190",
          "weight": "80"
        },
        "id": "Jordan"
      },
      {
         "atti": {
          "high": "190",
          "weight": "80"
        },
        "id": "Jordan"
      }
    ]
  },
  {
    "id": "id2",
    "devices": [
      {
         "atti": {
          "high": "190",
          "weight": "80"
        },
        "id": "Jordan"
      }
    ]
  },
  {
    "id": "id3",
    "devices": [
      {
         "atti": {
          "high": "190",
          "weight": "80"
        },
        "id": "Jordan"
      }
    ]
  }
]

Input source as following:

["id1", "apple", "167"]
["id1", "carter", "203"]
["id1", "jason", "188"]
["id2", "paul", "178"]
["id3", "Jordan", "190"]

Pool template

[
  {
    "id": "id1",
    "devices": [
    ]
  },
  {
    "id": "id2",
    "devices": [
    ]
  },
  {
    "id": "id3",
    "devices": [
    ]
  }
]

Answer 1

Here:

for item in aDevList:
    aTempJson['id'] = item[1]
    aTempJson['atti']['high'] = item[2]

    for (i,pid) in enumerate(aPool):
      if pid['id'] == item[0]:
        aPool[i]['devices'].append(aTempJson)
        break

you are modifying the same aTempJson dict and appending it to the list over and over. What you have to do is to create a new dict for each item.