.. _`JSON to Table`:

.. _`org.sysess.sympathy.data.json.jsontotable`:

JSON to Table
`````````````

.. image:: json2table.svg
   :width: 48







Documentation
:::::::::::::

Convert a JSON file to a Table

There are two kinds of tables that can be created:

    * Single row – where the JSON structure is simply flattened
    * Multiple rows - where the JSON structure is recursively expanded to
      create several rows

If a single-row table is created, there is an option to minimize the
column names to remove unnecessary path information from the JSON keys.

For example from the JSON:

.. code-block:: python

    {
        "version":"1.0",
        "software":"sfd",
        "items" : {
            "a":"1",
            "b":"2",
             "c":"3"
        }
    }

we can create the following single-row table

.. code-block:: python

    version    software    items.a    items.b    items.c
    ----------------------------------------------------
    1.0        sfd         1          2          3

and the column names can be *minimized* to

 .. code-block:: python

    version    software    a    b    c
    -------------------------------------
    1.0        sfd         1    2    3


If a multiple rows-table is created, the recursive algorithm might identify
keys and therefore columns that are lacking some values. One can choose to
fill in the missing values with a **empty string**, a **nan** string or
**mask** the value.

For example from the JSON:

.. code-block:: python

    {
        "version":"1.0",
        "software":"sfd",
        "items" : [
            {
                "a":"1",
                "b":"2",
                "c":"3"
            },
            {
                "a":"67",
                "b":"77",
                "d":"97"
            }
        ]
    }

we can create the following multiple-rows table

.. code-block:: python

    version    software    a    b    c    d
    -------------------------------------------
    1.0        sfd         1    2    3    ---
    1.0        sfd         67   77   ---  97

where the ``c`` column is masked in the second row and the ``d``
column is masked in the first row.

If the algorithm that creates tnhe multi-row table fails to produce
the desired table, it might be worth using other nodes to remove,
select or split the JSON structure on some key.


Definition
::::::::::


Input ports
...........

    **input**  json
        Input JSON object


Output ports
............

    **output**  table
        Output table




Configuration
.............

    **Minimize colum names** (minimize_col_names)
        Create column names that are minimal
    **Use zero-like values instead of masks** (nomask)
        When unchecked data cells that are missing will be masked. When checked such cells are instead assigned 0, 0.0, False, "", etc. depending on the type of the value column.
    **(no label)** (table_kind)
        What kind of table to create








Implementation
..............

.. automodule:: node_json2table
    :noindex:

.. class:: JsonToTable
    :noindex: