Python
As an economics graduate students, I spent 6 years trying to become an expert in Stata. Then, I realized that no one in life outside academia cares about Stata. So I decided to teach myself Python.
Below are some resources that I used and some notes I generated:
Python Data Science Handbook by Jake VenderPlas provides a great introduction to Python commands for beginners.
This is a crosswalk of commands from Stata to Python that I created - organized version of my notes.