I have a PhD in economics. I am currently learning Julia. I use R, Python and Maple on a regular basis. I once was into Matlab and Stata.
Slides for an introductory course on econometrics
publicly available material
Cheatsheets for MITx MicroMasters Capstone
Notes to accompany Thomas Piketty, Capital in the Twenty-First Century (Harvard University Press, 2014)
Gran Diccionari de la llengua catalana (Kindle LookUp Edition): Python code to edit the commercial ebook into a lookup dictionary for the Catalan language for use with a Kindle Paperwhite 2018 and other compatible ebook readers.