---
title: How I Learned R
date: '2017-12-09'
slug: how-i-learned-r
---

This week a neighbor of mine told me he wanted to learn R, and asked me how I learned R. I realized I had never blogged about it, so here we go. I learned R through a rather unusual way: I mostly learned R by answering other people's questions.

R was introduced to me in 2004 in a course on statistical computing when I was an undergraduate. Before that, we were taught a little bit S. We didn't learn these languages systematically, but that was fine. After you learn what a numeric vector is and how to write a for loop, you can already do a lot of things.

Most of my classmates didn't continue to learn R after the course, but I did, mostly because I built a web forum in Chinese, and some people asked questions there. Of course, I was not knowledgeable enough to answer all questions, but I knew how to use two things: the R help pages, and Google. Through this process of finding answers for other people, I learned a lot more about R. I just kept doing that for a couple more years. And "a couple more" is 13 --- Yes, this web forum is still alive, and I'm still answering questions there, although I'm no longer able to answer that many.

To be honest, I have never finished reading a single tutorial or book on R. There was only one exception: in 2007, I felt I should read something like that, so I went to the [contributed documentation](https://cran.rstudio.com/other-docs.html) on CRAN, and hoped to read at least the short documents one by one. I started with the first one, "Using R for Data Analysis and Graphics -- Introduction, Examples and Commentary", written by John Maindonald. I finished it, found some minor mistakes, and wrote to John.[^1] Other than that 100-page document, I haven't managed to finish other documents or books. That is why I don't have an answer when beginners ask me for recommendations on R books. 

In the early days, I was motivated to answer questions because of praises. Not many people knew R at that time in China. I became an "expert", although they didn't know that I was just doing copy-and-paste from R help pages and Google searches.

Charlie Munger seems to quote Benjamin Franklin frequently:

> "If you would persuade, you must appeal to interest rather than intellect."

I think the same idea can be applied to learning something new: you can appeal to interest (in the sense of advantages or benefits) instead of other things. The "interest" in my early days was the praises. I felt good about them. That is it.

BTW, this also explains [my reward to Yihan](https://stackoverflow.com/a/47109231/559676) on Stack Overflow. It is good to see beginners help beginners, and this behavior should be strongly encouraged.

[^1]: That was how we got to know each other. Seven years later, I invited him to give a talk at the China R Conference in Beijing, and we met for the first time in person there.
