Merge JSON data with Python

Question

As part of a Python program, I want to merge JSON objects that contain identically structured data. For instance:

{
    "responseStatus": "SUCCESS",
    "responseDetails": {
        "total": 5754,
    },
    "data": [
        {
            "id": 1324651
        },
        {
            "id": 5686131
        }
    ]
}

What I want to do is to add the content of the data array of my section object into the data array of my first object.

So, assuming:

thejson1 = json.loads({"responseStatus": "SUCCESS","responseDetails": {"total": 5754,},"data": [{"id": 1324651},{"id": 5686131}]})
thejson2 = json.loads({"responseStatus": "SUCCESS","responseDetails": {"total": 1234,},"data": [{"id": 2165735},{"id": 2133256}]})

I thought that executing:

thejson1["data"].append(thejson2["data"])

Would expand thejson1 into:

{
    "responseStatus": "SUCCESS",
    "responseDetails": {
        "total": 5754,
    },
    "data": [
        {
            "id": 1324651
        },
        {
            "id": 5686131
        },
        {
            "id": 2165735
        },
        {
            "id": 2133256
        }
    ]
}

But what it does instead is add thejson2 data as an array within the data array of thejson1:

{
    "responseStatus": "SUCCESS",
    "responseDetails": {
        "total": 5754,
    },
    "data": [
        {
            "id": 1324651
        },
        {
            "id": 5686131
        },
        [
            {
                "id": 2165735
            },
            {
                "id": 2133256
            }
        ]
    ]
}

So, what am I doing wrong? It looks like append adds the data array of the second JSON object instead of its content, but note that I can't know in advance the contents of the "data" array in my JSON input, so I can't write code that specifically loops in the "id" objects to add them one by one.

Thanks in advance!

R.

Possible duplicate of Difference between append vs. extend list methods in Python — Grigoriy Mikhalkin
– Grigoriy Mikhalkin, Commented Apr 13, 2018 at 8:13

Taku · Accepted Answer · 2018-04-13 08:15:47Z

9

You're looking for extend, not append.

thejson1["data"].extend(thejson2["data"])

append takes the single argument and insert it to the end. While extend extends the list by adding all the individual values in the argument list to the end.

# example:
a=[1, 2, 3]

b = a[:].append([4, 5])
# b = [1, 2, 3, [4, 5]]

c = a[:].extend([4, 5])
# c = [1, 2, 3, 4, 5]

edited Apr 13, 2018 at 8:15

answered Apr 13, 2018 at 8:10

Taku

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Comments

Rakesh · Accepted Answer · 2018-04-13 08:18:25Z

1

thejson1 = {"responseStatus": "SUCCESS","responseDetails": {"total": 5754,},"data": [{"id": 1324651},{"id": 5686131}]}
thejson2 = {"responseStatus": "SUCCESS","responseDetails": {"total": 1234,},"data": [{"id": 2165735},{"id": 2133256}]}

thejson1["data"]  += thejson2["data"]

Output:

{'responseDetails': {'total': 5754}, 'data': [{'id': 1324651}, {'id': 5686131}, {'id': 2165735}, {'id': 2133256}], 'responseStatus': 'SUCCESS'}

You can also use += to extend.

edited Apr 13, 2018 at 8:18

answered Apr 13, 2018 at 8:11

Rakesh

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