#python #data

Greg Wilson was soliciting strategies for lazy-loading datasets in Python modules. There are, of course, many ways to do this, but I didn't see this one being discussed.

Since Python 3.7 (released in 2017) you can define a module-level __getattr__ function that gets used for name resolution (see PEP 562). You can use this to call a data-loading function the first time each module-level property is accessed. This implementation uses only functions, dicts, and the one magic “dunder” function, which might be more approachable than programming with classes (depending on your audience).