Given a JSON list of objects, flatten any keys which always contain single item arrays to just a single value

Install this tool using pip:

$ pip install flatten-single-item-arrays

This will output the rewritten JSON:

$ flatten-single-item-arrays input.json

You can save it to a file like this:

$ flatten-single-item-arrays input.json > output.json

Use --debug to see extra debugging information displayed on standard error:

$ flatten-single-item-arrays input.json --debug > output.json
Item count: 2
count_of_single_item_lists
{
    "foo": 2
}
count_of_present_keys
{
    "foo": 2,
    "bar": 2
}
keys_to_reformat:
- foo

This tool accepts the path to a JSON file and outputs a modified version of that JSON file where any keys that are always single item lists are rewritten to a single value.

For example, the following input:

[
    {
        "foo": [
            "bar"
        ],
        "bar": 5
    },
    {
        "foo": [
            "baz"
        ],
        "bar": 6
    }
]

Will be transformed to this:

[
    {
        "foo": "bar",
        "bar": 5
    },
    {
        "foo": "baz",
        "bar": 6
    }
]

I built this to help work with data from the Airtable API, which often contains this single-item-list pattern.

To contribute to this tool, first checkout the code. Then create a new virtual environment:

cd flatten-single-item-arrays
python -mvenv venv
source venv/bin/activate

Or if you are using pipenv:

pipenv shell

Now install the dependencies and tests:

pip install -e '.[test]'

To run the tests:

pytest