maton.py: Dump MATLAB files to JSON for using with basically anything else.

maton.py

#!/usr/bin/env python
from __future__ import division, print_function

import click
import numpy as np
import scipy.io as sio
import json

def transform_data(data):
    if isinstance(data, dict):
        return {
            key: transform_data(value)
            for key, value in data.items()
        }
    elif isinstance(data, np.ndarray):
        if data.dtype.fields:
            return {
                key: transform_data(data[key])
                for key in data.dtype.fields
            }
        else:
            if data.shape == ():
                # 0d arrays are scalars, so unpack them.
                return transform_data(data[()])
            else:
                return [
                    transform_data(row)
                    for row in data
                ]
    # Base case, no transformation needed.
    return data

@click.command()
@click.argument("filename", click.Path(exists=True, dir_okay=False, file_okay=True))
@click.option("--pretty", is_flag=True)
def main(filename, pretty):
    data = sio.loadmat(filename, squeeze_me=True)

    json_kwargs = {
        'sort_keys': True,
        'indent': 2
    } if pretty else {}

    print(json.dumps(transform_data(
        data
    ), **json_kwargs))

if __name__ == "__main__":
    main()