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    "# Conda and pip - managing environments\n",
    "\n",
    "**Environment:** \"the world around you\". In the Python context, a way to define all the tools and libraries that will be loaded when code is run, in a manner that makes it possible to reload them later in a predictable and reproducible fashion.  This requires being able to both describe the necessary packages and to install/remove them.\n",
    "\n",
    "**Conda:** a tool to install packages and to manage environments.  Open source, developed by Anaconda (a company).  It can manage not only Python packages but also R, C tools and more.  The [canonical conda docs](https://conda.io/docs/user-guide/tasks/manage-environments.html).\n",
    "\n",
    "**Pip:** the Python packaging tool, it only installs/removes Python packages, hosted at the [Python Package Index (PyPI)](https://pypi.python.org/pypi).\n",
    "\n",
    "\n",
    "## We will mostly use Conda\n",
    "\n",
    "For managing our environments and dependencies.  But we may need to occasinally install packages with `pip` if they aren't available via Conda.\n",
    "\n",
    "One important note: `conda create` and `conda env create` are very similar, but not identical (this is for historical reasons, they are being now merged).  To create a new environment based on a few packages specified at the command line, use e.g.:\n",
    "\n",
    "    conda create -n myenv python=3.6 notebook pandas\n",
    "    \n",
    "but to create an env based on an `environment.yml` file, use:\n",
    "\n",
    "    conda env create -f environment.yml\n",
    "    \n",
    "You can bootstrap the creation of the `environment.yml` file from an existing environment by using:\n",
    "\n",
    "    conda env export > environment.yml\n",
    "    \n",
    "A key feature of using `environment.yml` is that you can specify within it not only packages installed with Conda, but also with pip.\n",
    "\n",
    "Here's an example of a simple `environment.yml` file:\n",
    "\n",
    "```\n",
    "name: example-environment\n",
    "\n",
    "dependencies:\n",
    "  - python==3.4\n",
    "  - numpy\n",
    "  - toolz\n",
    "  - matplotlib\n",
    "  - dill\n",
    "  - pandas\n",
    "  - partd\n",
    "  - bokeh\n",
    "  - pip:\n",
    "    - git+https://github.com/blaze/dask.git#egg=dask[complete]\n",
    "    - jupyterlab\n",
    "```\n",
    "\n",
    "To see your environments: `conda info -e`.\n",
    "\n",
    "To remove an environment: `conda remove -n example-environment --all`."
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