Python interoperability in Swift

README.md

Python interoperability

Check out this tutorial demonstrating Python interoperability in Swift.

Python library version details

PythonLibrary.useVersion

This function is intended to set the Python version before any references to the global PythonInterface called Python - it cannot be used to switch Python versions dynamically.

This could be better designed/documented so that people don't get the impression that switching Python versions is possible.

Special environment variables (defined here)

• PYTHON_LIBRARY (sets the Python library path, useful for setting a specific Python version)

  Anaconda:

  export PYTHON_LIBRARY="~/anaconda2/lib/libpython2.7.so"
  export PYTHON_LIBRARY="~/anaconda3/lib/libpython3.7m.so"
  
  

  Miniconda (osx):

  export PYTHON_LIBRARY="~/miniconda3/lib/libpython3.7m.dylib"
  export PYTHON_LIBRARY="~/miniconda2/lib/libpython2.7.dylib"
  

Then, rerun Swift.

• PYTHON_VERSION (forces a specific Python version)
• PYTHON_LOADER_LOGGING (enables library loading debug log)

example.swift

// First, run `wget https://via.placeholder.com/150.png` and `pip3 install pillow`.

import Python
PythonLibrary.useVersion(3)
print(Python.version)
// 3.7.2 (default, Feb 12 2019, 08:16:38)
// [Clang 10.0.0 (clang-1000.11.45.5)]

let PIL_Image = Python.import("PIL.Image")
let image = PIL_Image.open("150.png")
print(image.format, image.size, image.mode)
// PNG (150, 150) P