clear_notebook

#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
simple script for clearing all cells of an ipython notebook

Usage: `clear_notebook fname_in.ipynb [fname_out.ipynb]`
"""
import sys

from IPython.nbformat.current import reads, writes


def clear_outputs(fname_in, fname_out=None, clear_prompt_numbers=True):
    """
    clears the output of all cells in an ipython notebook

    Parameters:
    ===========

    fname_in: string
        filename of the incoming notebook

    fname_out: string, optional
        filename of the outgoing notebook
        (default: fname_in)

    clear_promt_numbers: bool, optional
        clears the prompt numbers of all cells
        (default: True)
    """
    if fname_out is None:
        fname_out = fname_in

    with open(fname_in) as nb_file:
        notebook = reads(nb_file.read(), 'json')

    for wsheet in notebook.worksheets:
        for cell in wsheet.cells:
            if cell.get('cell_type', None) == 'code':
                cell.outputs = []
                if clear_prompt_numbers is True:
                    cell.pop('prompt_number', None)

    with open(fname_out, 'w') as out:
        out.write(writes(notebook, 'ipynb'))


if __name__ == '__main__':
    FNAME_IN = sys.argv[1]
    if len(sys.argv) > 2:
        FNAME_OUT = sys.argv[2]
    else:
        FNAME_OUT = None

    print "clearing {}".format(FNAME_IN)
    clear_outputs(FNAME_IN, FNAME_OUT)