# Phoning it in with R

## Running R and Emacs on my mobile phone

Recently I have been running R from my Android phone. There are some apps on the Google Play Store that seem to let you emulate R, or connect to a remote version. Instead of doing that, I have been running R directly off my phone using the terminal.

I tried a couple things, but I found the Termux app to be the most stable solution. With Termux I’m able to emulate a Linux command line and call programs like R and Emacs.

I told Dr Hua Kiefer about it, but she wasn’t so impressed:

## Why bother

Why bother with this at all?

Usually I am not far away from my desk and my reliable computer. Do I really need to run it from my phone? What is the added benefit? There are a few reasons

• It’s cool
• Having R with you is handy, you can
• Look up stats on the fly (no dealing with clunky UI if data API available)
• Create custom plots on the fly
• Run simulations on the go
• With Emacs you can
• Edit text files wherever you are
• Hone your Emacs text editing skills

Since I’ve got my phone with me most times, now can have R with me most times. That makes me happy.

## Keyboards

The default keyboard on my Android Phone is good for making good Tweets or sending text messages but not good for editing files. I found two solutions:

• The Hacker Keyboard app LINK
• A Bluetooth keyboard (I got this one Amazon, it seems all right)

Following helpful suggestion online I installed the Hacker Keyboard. This replaced my puny keyboard with a much more robust version.

As good as the Hacker Keyboard is I also bought a little portable Bluetooth keyboard that can pair with my phone. The version I bought is nice and compact. The only downside is the “t” and “v” keys are a little smaller to accommodate the joints where the keyboard folds. That means I tend to miss those keys if I don’t push them hard enough. I think I’ll get used to it and adapt.

## Emacs

I usually use the Rstudio IDE, but as far as I know it is not available on mobile. Fortunately Termux comes with Emacs readily available. After installing it I fired it up and in short order had my first program:

I used to use Emacs years ago, mostly for SAS code. As I haven’t written much SAS code lately I haven’t used Emacs much.

Messing around over the past few days I have begun to recall the Emacs that I forgot. It’s a joy to work with, reminding me of simpler times.

Plus it has games:

## How to do it

I am afraid this cannot be a comprehensive guide. The steps I took might not work for your particular setup. I had to use a lot of trial and error to get things working.

However, after some searching (starting with this Reddit post: R on the go) I found that staying pretty close to the steps outlined in the Termux Wiki I was able to get things working. There’s still a few places were things are not working (I have trouble installing certain packages from CRAN). But in general things seem to be working pretty well.

# What to do with it

Now that I was up an running, what could we do besides play Tetris?

Fortunately I was able to get the quantmod package working. That means I can easily got to FRED and get economic series.

FRED of course, has a nice application. But I find customizing charts on the phone not the best experience. By loading the data into R we can write our own custom script.

library(tidyverse)
library(lubridate)
quantmod::getSymbols('MORTGAGE30US', src='FRED')
df <-data.frame(date=time(MORTGAGE30US),MORTGAGE30US)
png(filename='mtg2.png', height=500,width=800)
ggplot(data=df%>% filter(year(date)>2009),
aes(x=date,y=MORTGAGE30US))+
geom_line(color='dodgerblue',size=1.2)+
theme_minimal(base_size=18)+
theme(plot.caption=element_text(hjust=0))+
geom_hline(linetype=2,
color='dodgerblue',
aes(yintercept=last(MORTGAGE30US)))+
labs(x='',y='rate %',
title='30-year fixed mortgage rate (%)',
caption='@lenkiefer Source Freddie Mac')
dev.off()

Most of this post was written on my phone via Emacs