3.1. How to create virtual environments for python with conda¶
In this section we will explain how to work with virtual environments using conda. A virtual environment is a named, isolated, working copy of Python that maintains its own files, directories, and paths so that you can work with specific versions of libraries or Python itself without affecting other Python projects. Virtual environments make it easy to cleanly separate different projects and avoid problems with different dependencies and version requirements across components. The conda command is the preferred interface for managing installations and virtual environments with the Anaconda Python distribution. If you have a vanilla Python installation or other Python distribution see virtualenv.
In the following we assume that the Anaconda Python distribution installed and accessible.
3.1.1. Check conda is installed and in your PATH.¶
Open a terminal client.
Enter conda -V into the terminal command line and press enter.
If conda is installed you should see somehting like the following.
$ conda -V
conda 4.6.8
3.1.2. Check conda is up to date.¶
In the terminal client enter
conda update conda
Update any packages if necessary by typing y to proceed.
3.1.3. Create a virtual environment for your project.¶
In the terminal client enter the following where yourenvname is the
name you want to call your environment, and replace x.x with the Python
version you wish to use. (To see a list of available python versions
first, type conda search "^python$" and press enter.)
conda create -n yourenvname python=x.x anaconda
Press y to proceed. This will install the Python version and all
the associated anaconda packaged libraries at
path_to_your_anaconda_location/anaconda/envs/yourenvname
3.1.4. Activate your virtual environment.¶
To activate or switch into your virtual environment, simply type the following where yourenvname is the name you gave to your environement at creation.
conda activate yourenvname
Activating a conda environment modifies the PATH and shell variables
to point to the specific isolated Python set-up you created. The
command prompt will change to indicate which conda environemnt you
are currently in by prepending (yourenvname). To see a list of all
your environments, use the command conda info -e.
3.1.5. Install additional Python packages to a virtual environment.¶
To install additional packages only to your virtual environment,
enter the following command where yourenvname is the name of your
environemnt, and [package] is the name of the package you wish to
install. Failure to specify -n yourenvname will install the
package to the root Python installation.
conda install -n yourenvname [package]
3.1.6. Deactivate your virtual environment.¶
To end a session in the current environment, enter the following. There is no need to specify the envname - which ever is currently active will be deactivated, and the PATH and shell variables will be returned to normal.
conda deactivate
3.1.7. Delete a no longer needed virtual environment.¶
To delete a conda environment, enter the following, where yourenvname is the name of the environment you wish to delete.
conda remove -n yourenvname -all