bamboo-nested 0.0.7

A project for feeding various nested data formats into pandas

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## bamboo

[](https://pypi.org/project/bamboo-nested/)
[](https://travis-ci.org/mvilim/bamboo)

bamboo is a library for feeding nested data formats into pandas. The space of data representable in nested formats is larger than the space covered by pandas. pandas supports only data representable in a flat table (though things like multi-indexs allows certain types of tree formats to be efficiently projected into a table). Data which supports arbitrary nesting is not in general convertible to a pandas dataframe. In particular, data which contains multiple repetition structures (e.g. JSON arrays) that are not nested within each other will not be flattenable into a table.

As a simple example

The current data formats supported are:
* JSON
* Apache Avro
* Apache Arrow
* Profobuf (via [PBD](https://github.com/mvilim/pbd))

bamboo works by projecting a flattenable portion (a subset of the nested columns) of the data into a pandas dataframe. By projecting various combinations of columns, one can make use of all the relationships implied by the nested structure of the data.

### Installation

To install from PyPI:

```
pip install bamboo-nested
```

### Example

A minimal example of flattening a JSON string:

```
from bamboo import from_json

obj = [{'a': None, 'b': [1, 2], 'c': [5, 6]}, {'a': -1.0, 'b': [3, 4], 'c': [7, 8]}]
node = from_json(json.dumps(obj))
> - a float64
> - b []uint64
> - c []uint64
```

Flattening just the values of column `a`:

```
df_a = node.flatten(include=['a'])
> a
> 0 NaN
> 1 -1.0
```

Flattening columns `a` and `b` (note that column `a` is repeated to match the corresponding elements of column `b`):

```
df_ab = node.flatten(include=['a', 'b'])
> a b
> 0 NaN 1
> 1 NaN 2
> 2 -1.0 3
> 3 -1.0 4
```

Trying to flatten two repetition lists at the same level will lead to an error (as this structure is unflattenable without taking a Cartesian product):

```
df_bc = node.flatten(include=['b', 'c'])
> ValueError: Attempted to flatten conflicting lists
```

### Building

To build this project:

Building from source requires cmake (`pip install cmake`) and Boost.

```
python setup.py
```

### Unit tests

To run the unit tests:

```
python setup.py test
```

or use nose:

```
nosetests python/bamboo/tests
```

### Licensing

This project is licensed under the [Apache 2.0 License](https://github.com/mvilim/bamboo/blob/master/LICENSE). It uses the pybind11, Arrow, Avro, nlohmann JSON, and PBD projects. The licenses can be found in those [projects' directories](https://github.com/mvilim/bamboo/blob/master/cpp/thirdparty).