dotfiles/lang/python

Python Tooling

Contets

• Python Scripts
• Working with Python
• Working with pyenv
• Working with pip
• Useful Links
• TODOs

Python Scripts

To convert a directory of .blend files to .obj file using the script provided within this directory

for i in *.blend;
  /Applications/Blender.app/Contents/MacOS/Blender $i --background \
  --python convert_blend_to_obj.py -- $i.obj
end

Working with Python 🔝

To syntax check a python script / file

python -m py_compile [mr_fancy_python_script]

Working with virtual envs

❗️ If the root / parent directory for virtualenv directories is renamed then more than likely all virtualenvs will be broken due to hardcoded paths in the activate python scripts, see this for a possible solution.

Working with pyenv 🔝

To update the pyenv python version manager to the latest git master

cd $PYENV_ROOT; git pull upstream; git push origin master;

The above commands are useful for updating the list of installable pythons

To list installable Python versions

pyenv install -l

To download and keep the source for a particular python version and print build output to $STDOUT

pyenv install -kv [MARJOR.MINOR.PATCH]

The source for a particular Python is downloaded in `$PYENV_ROOT/sources/[MAJOR.MINOR.PATCH]/Python-[MAJOR.MINOR.PATCH]

• ❗️ UPDATE August 29, 2019

  When building Python on macOS that has multiple versions of Xcode installed ie. 10.1 10.2 and 10.3 complications can arise where certain command line tools are used or may not be installed for whatever reason. Try using the below command to build a version of Python 2.7.x or 3.7.x using the tooling provided by Xcode

  env \
  SDKROOT=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk \
  MACOSX_DEPLOYMENT_TARGET=10.14 \
  pyenv install [MAJOR.MINOR.PATCH]
  

protip when installing a version of python on macOS /usr/local/{sbin/bin} should be in the $PATH or pyenv will fail to build python due to SSL errors. However the opposite is true for Debian with linuxbrew installed and setup.

To install Python 2.7.15 on Debian Stretch 9.4 using pyenv make certain that linuxbrew pythons ARE NOT in the users $PATH when using pyenv to install a particular version of python.

To list local python versions available to pyenv

pyenv versions

To delete an old virtualenv setup with pyenv

pyenv uninstall neovim3

To set multiple python interpreters for a system / shell, edit $HOME/.python-version and add the versions of python you would to be accessible from a shell.

Example

2.7.15
3.7.2

Working with pyenv virtualenvs

There is a plugin for pyenv that can be used to setup virtualenvs for python.

To setup a virtualenv of the name py3my-virtualenv

pyenv virtualenv 3.7.3 py3my-virtualenv
echo "to activate the virtualenv"
pyenv activate py3my-virtualenv
echo "to deactivate the virtualenv
pyenv deactivate

To list all available local virtualenvs on a box

pyenv versions

To install a Python package inside a virtualenv

pip install neovim3
echo "to upgrade the neovim3 package"
pip install --upgrade neovim

Working with pip

To list all top level packages that have been installed with pip

pip list

To list outdated packages that have been install via pip

pip list --outdated

To upgrade a package that has been installed with pip

pip install --upgrade [NAME_OF_PACKAGE]
pip install -U [NAME_OF_PACKAGE]

To list all versions of a package that can be installed via pip

pip install --no-deps [NAME_OF_PACKAGE]==x.x.x
echo "below is an example"
pip install --no-deps numpy==x.x.x

To install a locally downloaded copy of a package and use local paths, learn more

pip install -r requirements.txt --no-index --find-links file:///tmp/packages

To upgrade all outdated pip packages copy pasta

pip list --format freeze --outdated | sed 's/=.*//g' | xargs -n1 pip install -U

Useful Links

• **debugging python scripts/files using vscode
• https://pythondev.readthedocs.io/debug_tools.html (a good resource for debugging / tshooting c c++ projects that interopt with python)
• https://www.pythonguis.com/tutorials/pyside-creating-your-first-window/ (dencent tutorials for working with pyside)

TODOs 🔝