Python environments
Interpreters
To install different Python interpreters I strongly recommend asdf1.
Let's look at to install Python in two different OSes, macOS and Fedora.
macOS
To install asdf on a macOS, first install the general dependencies with
$ brew install coreutils curl git
then install asdf itself with
$ brew install asdf
Add to the shell, in our case zsh with:
$ echo -e "\n. $(brew --prefix asdf)/asdf.sh" >> ~/.zshrc
Add a plugin, in our case Python, with
$ asdf plugin add Python
You can list all available versions with
$ asdf list all Python
Install a specific version, say,
$ asdf install Python 3.9.0
Fedora
To install asdf on a Fedora, first install the general dependencies
$ sudo dnf install curl git
Clone the repository
$ git clone https://github.com/asdf-vm/asdf.git \
~/.asdf --branch v0.8.0
Add to zsh with
$ . $HOME/.asdf/asdf.sh`
pyenv
Compiling on macOS
pyenv can be notoriously problematic on macOS. For instance, running pyenv doctor on my laptop2 will result in:
Cloning ~/.pyenv/plugins/pyenv-doctor/bin/.....
Installing python-pyenv-doctor...
python-build: use readline from homebrew
python-build: use zlib from xcode sdk
BUILD FAILED (OS X 10.15.7 using python-build 20180424)
Inspect or clean up the working tree at /var/folders/c2/9d2fsqt57t10zn1f2ylp1jxw0000gn/T/python-build.20210128094523.17091
Results logged to /var/folders/c2/9d2fsqt57t10zn1f2ylp1jxw0000gn/T/python-build.20210128094523.17091.log
Last 10 log lines:
checking readline/readline.h, presence... no
checking for readline/readline.h,... no
checking readline/rlconf.h usability... yes
checking readline/rlconf.h presence... yes
checking for readline/rlconf.h... yes
checking for SSL_library_init in -lssl... no
configure: WARNING: OpenSSL <1.1 not installed. Checking v1.1 or beyond...
checking for OPENSSL_init_ssl in -lssl... no
configure: error: OpenSSL is not installed.
make: *** No targets specified and no makefile found. Stop.
Problem(s) detected while checking system.
See https://github.com/pyenv/pyenv/wiki/Common-build-problems for known solutions.
The problem in this case is that pyenv can't find the relevant C headers for compilation of new versions. This can be fixed by using:
$ CFLAGS="-I$(brew --prefix openssl)/include \
-I$(brew --prefix readline)/include \
-I$(xcrun --show-sdk-path)/usr/include" \
LDFLAGS="-L$(brew --prefix openssl)/lib \
-L$(brew --prefix readline)/lib \
-L$(xcrun --show-sdk-path)/usr/lib" \
pyenv doctor
and the output will be:
Cloning ~/.pyenv/plugins/pyenv-doctor/bin/.....
Installing python-pyenv-doctor...
python-build: use readline from homebrew
python-build: use zlib from xcode sdk
Installed python-pyenv-doctor to /var/folders/c2/9d2fsqt57t10zn1f2ylp1jxw0000gn/T/pyenv-doctor.20210128095003.18889/prefix
Congratulations! You are ready to build pythons!
Poetry
Poetry as Jupyter kernel
To register a poetry environment (named foo) as a Jupyter kernel, run:
poetry run python -m ipykernel install --user --name foo
venv
Create a new venv with the command:
$ virtualenv venv
and activate it using (under Bash or zsh) with:
$ source venv/bin/activate
Anaconda
First download Anaconda (or Miniconda). Once installed you can proceed to create environments3.
Creating environments
An environment foo can be created using
conda create --name foo
One it is created, it can be activated using
conda activate foo