3.2.8. Notes#

You will need to update these packages manually#

Packages installed in this manner should also be updated manually.

When you notice there is an update for the package, for example, from the project’s website or from their source code repository, follow the steps in Updating an installed package to install the latest version.

Why pip3 and not pip?#

The pip package includes the following commands:

  • pip3 — Python 3 version

  • pip — Python 2 version

Support for Python 2 ended in January 2020.

Since there is a possibility for both commands to exist on a system, it is safer to use pip3 when installing packages using this method.

What about programs written in Python 2?#

Support for Python 2 ended in January 2020.

If you do need to use a program written only in Python 2, you can create an isolated environment — either using Python venv or Conda and then install the package there.

Related sections:

When should I use a virtual environment?#

The method described here will not work if the programs you are installing require two different versions of the same package from PyPI.

In that case, you can consider creating an isolated environment — either using Python virtualenv or Conda and then installing the packages there.

Related sections:

Older versions of pip#

If the version of pip installed in your system is older than 20.0, it will attempt to install packages in system paths by default, resulting in permission denied errors.

To avoid that, you will need to add the --user option to the install and uninstall commands, for example:

pip3 install --user biopython

A better approach is to upgrade your local version of pip. Once upgraded, you will no longer need to user --user.

To upgrade pip, do:

pip3 install --user -U pip

You can check the installed version of pip using:

pip3 -V