Managing Python

Conda treats Python the same as any other package, so it is easy to manage and update multiple installations.

Anaconda supports Python 2.7, 3.6, 3.7, and 3.8. The default is Python 2.7 or 3.8, depending on which installer you used:

  • For the installers "Anaconda" and "Miniconda," the default is 2.7.

  • For the installers "Anaconda3" or "Miniconda3," the default is 3.8.

Viewing a list of available Python versions

To list the versions of Python that are available to install, in your terminal window or an Anaconda Prompt, run:

conda search python

This lists all packages whose names contain the text python.

To list only the packages whose full name is exactly python, add the --full-name option. In your terminal window or an Anaconda Prompt, run:

conda search --full-name python

Installing a different version of Python

To install a different version of Python without overwriting the current version, create a new environment and install the second Python version into it:

  1. Create the new environment:

    • To create the new environment for Python 3.9, in your terminal window or an Anaconda Prompt, run:

      conda create -n py39 python=3.9 anaconda
      

      Note

      Replace py36 with the name of the environment you want to create. anaconda is the metapackage that includes all of the Python packages comprising the Anaconda distribution. python=3.9 is the package and version you want to install in this new environment. This could be any package, such as numpy=1.19, or multiple packages.

    • To create the new environment for Python 2.7, in your terminal window or an Anaconda Prompt, run:

      conda create -n py27 python=2.7 anaconda
      
  2. Activate the new environment.

  3. Verify that the new environment is your current environment.

  4. To verify that the current environment uses the new Python version, in your terminal window or an Anaconda Prompt, run:

    python --version
    

Installing PyPy

To use the PyPy builds you can do the following:

conda config conda config --add channels conda-forge
conda config --set channel_priority strict
conda create -n pypy pypy
conda activate pypy

Using a different version of Python

To switch to an environment that has different version of Python, activate the environment.

Updating or upgrading Python

Use the terminal or an Anaconda Prompt for the following steps.

If you are in an environment with Python version 3.4.2, the following command updates Python to the latest version in the 3.4 branch:

conda update python

The following command upgrades Python to another branch---3.8---by installing that version of Python. It is not recommended, rather it is preferable to create a new environment. The resolver has to work very hard to determine exactly which packages to upgrade. But it is possible, and the command is:

.. code-block:: bash

conda install python=3.8