When creating a Python package, I am told to create a blank file called init.py. What I don't understand is why I need to create this file. The distutils build script doesn't modify it, so five builds later it's still blank. What is it's purpose?
It a signal to Python that the folder is a package, not just a folder.
It also contains initialization code that is run when the package is imported into a script.
See the docs on the subject for more. The most relevant extract:
The
__init__.pyfiles are required to make Python treat the directories as containing packages; this is done to prevent directories with a common name, such asstring, from unintentionally hiding valid modules that occur later on the module search path. In the simplest case,__init__.pycan just be an empty file, but it can also execute initialization code for the package or set the__all__variable, described later.