G
Environments
Using environments is a great way to work with different versions of Python and/or packages. It also provides an isolated environment to install everything so that if something goes wrong, it won’t affect the rest of the system. Python environments are particularly handy when you need different versions of packages installed across different projects. You can also use environments to see all the package dependencies.
G.1 Conda Environments
The Anaconda Python distribution comes with conda. The “Getting Started” guide is a useful resource in this case.1 If you installed Anaconda with Python 3 (Appendix B), this appendix will show you how to create a separate environment that has a different version of Python in it. If we run python in the command line, we will begin with Python 3.9. Your exact version will differ from that shown in this book.
1. https://conda.io/projects/conda/en/latest/user-guide/getting-started.html
% python
Python 3.9.12 (main, Jun 1 2022, 06:34:44)
[Clang 12.0.0 ] :: Anaconda, Inc. on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>To create a new environment we run the conda command from the command line. We use the create command within conda and specify a --name for the environment. Here we are naming our Python environment py38. By default, the system will create a Python 3.9 environment, so we have to specify our Python version with python=3.8.
# type this in the (bash) terminal, not in python
conda create -n py38 python=3.8After running the command, you will see the following output.
Collecting package metadata (current_repodata.json): done
Solving environment: done
## Package Plan ##
environment location: /Users/danielchen/anaconda3/envs/py38
added / updated specs:
- python=3.8
The following packages will be downloaded:
package | build
---------------------------|-----------------
ca-certificates-2022.07.19 | hca03da5_0 124 KB
certifi-2022.6.15 | py38hca03da5_0 153 KB
libffi-3.4.2 | hc377ac9_4 106 KB
ncurses-6.3 | h1a28f6b_3 866 KB
openssl-1.1.1q | h1a28f6b_0 2.2 MB
pip-22.1.2 | py38hca03da5_0 2.5 MB
python-3.8.13 | hbdb9e5c_0 10.6 MB
setuptools-63.4.1 | py38hca03da5_0 1.1 MB
sqlite-3.39.2 | h1058600_0 1.1 MB
------------------------------------------------------------
Total: 18.6 MB
The following NEW packages will be INSTALLED:
ca-certificates pkgs/main/osx-arm64::ca-certificates-2022.07.19-hca03da5_0
certifi pkgs/main/osx-arm64::certifi-2022.6.15-py38hca03da5_0
libcxx pkgs/main/osx-arm64::libcxx-12.0.0-hf6beb65_1
libffi pkgs/main/osx-arm64::libffi-3.4.2-hc377ac9_4
ncurses pkgs/main/osx-arm64::ncurses-6.3-h1a28f6b_3
openssl pkgs/main/osx-arm64::openssl-1.1.1q-h1a28f6b_0
pip pkgs/main/osx-arm64::pip-22.1.2-py38hca03da5_0
python pkgs/main/osx-arm64::python-3.8.13-hbdb9e5c_0
readline pkgs/main/osx-arm64::readline-8.1.2-h1a28f6b_1
setuptools pkgs/main/osx-arm64::setuptools-63.4.1-py38hca03da5_0
sqlite pkgs/main/osx-arm64::sqlite-3.39.2-h1058600_0
tk pkgs/main/osx-arm64::tk-8.6.12-hb8d0fd4_0
wheel pkgs/main/noarch::wheel-0.37.1-pyhd3eb1b0_0
xz pkgs/main/osx-arm64::xz-5.2.5-h1a28f6b_1
zlib pkgs/main/osx-arm64::zlib-1.2.12-h5a0b063_2
Proceed ([y]/n)? y
Downloading and Extracting Packages
certifi-2022.6.15 | 153 KB | ########################## | 100%
python-3.8.13 | 10.6 MB | ########################## | 100%
openssl-1.1.1q | 2.2 MB | ########################## | 100%
setuptools-63.4.1 | 1.1 MB | ########################## | 100%
ca-certificates-2022 | 124 KB | ########################## | 100%
pip-22.1.2 | 2.5 MB | ########################## | 100%
sqlite-3.39.2 | 1.1 MB | ########################## | 100%
ncurses-6.3 | 866 KB | ########################## | 100%
libffi-3.4.2 | 106 KB | ########################## | 100%
Preparing transaction: done
Verifying transaction: done
Executing transaction: done
#
# To activate this environment, use
#
# $ conda activate py38
#
# To deactivate an active environment, use
#
# $ conda deactivateThe last few lines of the output tell you how you can use your newly created environment. If we run conda activate py38 from the command line now, our prompt will be prepended with our environment name. If we run python in the terminal to launch Python, you will see that a different version of Python is now being used.
% python
Python 3.8.13 (default, Mar 28 2022, 06:13:39)
[Clang 12.0.0 ] :: Anaconda, Inc. on darwin
Type "help", "copyright", "credits" or "license" for more information.To delete an environment, navigate to your anaconda3 folder. A folder there called envs stores all your environments. In this example, if we delete the py38 folder within envs, it’s as if we never created our environment, and it will be removed.
Within a given environment, any package or library we install (Appendix H) within it will be specific to that particular environment. Thus, we can have not only different versions of Python between environments but also different versions of libraries. You can create a separate Python environment (p4e for “Pandas for Everyone”) for this book as well.}
conda create --name p4e python=3You can install the libraries needed by following the instructions in Appendix H.
G.2 Pyenv + Pipenv
Calvin Hendryx-Parker gave a great talk at PyCon 2022 on Bootstrapping Your Local Python Environment that goes over the Pyenv setup with the pyenv-virtualenv plugin: https://www.youtube.com/watch?v=-YEUFGFHWgQ
The Hitchhiker’s Guide to Python and Real Python also have resources on using Pipenv for virtual environments: