Automatic creation of new code cells via widgets.

NewCodeCellWidget.ipynb

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   "source": [
    "# Automatic creation of new code cells via widgets\n",
    "\n",
    "This code was originally written by Jonathan Frederic. For full context, see [GH issue 4983 in IPython](https://github.com/ipython/ipython/issues/4983), as well as [5006](https://github.com/ipython/ipython/issues/5006) and [#44 in ipywidgets](https://github.com/ipython/ipywidgets/issues/44).\n",
    "\n",
    "The code below demonstrates quickly how to make a widget that injects a new code cell into the notebook."
   ]
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   "source": [
    "import base64\n",
    "from IPython.display import Javascript, display\n",
    "from IPython.utils.py3compat import str_to_bytes, bytes_to_str\n",
    "\n",
    "def create_code_cell(code='', where='below'):\n",
    "    \"\"\"Create a code cell in the IPython Notebook.\n",
    "\n",
    "    Parameters\n",
    "    code: unicode\n",
    "        Code to fill the new code cell with.\n",
    "    where: unicode\n",
    "        Where to add the new code cell.\n",
    "        Possible values include:\n",
    "            at_bottom\n",
    "            above\n",
    "            below\"\"\"\n",
    "    encoded_code = bytes_to_str(base64.b64encode(str_to_bytes(code)))\n",
    "    display(Javascript(\"\"\"\n",
    "        var code = IPython.notebook.insert_cell_{0}('code');\n",
    "        code.set_text(atob(\"{1}\"));\n",
    "    \"\"\".format(where, encoded_code)))"
   ]
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   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
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   "source": [
    "from ipywidgets import Button\n",
    "def on_click(button):\n",
    "    create_code_cell('print(\"Hello world!\")')\n",
    "    \n",
    "button = Button(description=\"Create code\")\n",
    "button.on_click(on_click)\n",
    "\n",
    "button"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
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   "outputs": [],
   "source": [
    "print(\"Hello world!\")"
   ]
  }
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