A tutorial on tidy cross-validation with R
Analyzing NetHack data, part 1: What kills the players
Analyzing NetHack data, part 2: What players kill the most
Dealing with heteroskedasticity; regression with robust standard errors using R
Easy time-series prediction with R: a tutorial with air traffic data from Lux Airport
Exporting editable plots from R to Powerpoint: making ggplot2 purrr with officer
Forecasting my weight with R
From webscraping data to releasing it as an R package to share with the world: a full tutorial with data from NetHack
Getting data from pdfs using the pdftools package
Getting the data from the Luxembourguish elections out of Excel
Going from a human readable Excel file to a machine-readable csv with {tidyxl}
How Luxembourguish residents spend their time: a small {flexdashboard} demo using the Time use survey data
Imputing missing values in parallel using {furrr}
Maps with pie charts on top of each administrative division: an example with Luxembourg's elections data
Missing data imputation and instrumental variables regression: the tidy approach
Searching for the optimal hyper-parameters of an ARIMA model in parallel: the tidy gridsearch approach
The best way to visit Luxembourguish castles is doing data science + combinatorial optimization
The year of the GNU+Linux desktop is upon us: using user ratings of Steam Play compatibility to play around with regex and the tidyverse
Using a genetic algorithm for the hyperparameter optimization of a SARIMA model
What hyper-parameters are, and what to do with them; an illustration with ridge regression
{pmice}, an experimental package for missing data imputation in parallel using {mice} and {furrr}
Building formulae
Functional peace of mind
Get basic summary statistics for all the variables in a data frame
Getting {sparklyr}, {h2o}, {rsparkling} to work together and some fun with bash
Importing 30GB of data into R with sparklyr
Introducing brotools
It's lists all the way down
It's lists all the way down, part 2: We need to go deeper
Keep trying that api call with purrr::possibly()
Lesser known dplyr 0.7* tricks
Lesser known dplyr tricks
Lesser known purrr tricks
Make ggplot2 purrr
Mapping a list of functions to a list of datasets with a list of columns as arguments
Predicting job search by training a random forest on an unbalanced dataset
Teaching the tidyverse to beginners
Why I find tidyeval useful
tidyr::spread() and dplyr::rename_at() in action
Easy peasy STATA-like marginal effects with R
Functional programming and unit testing for data munging with R available on Leanpub
How to use jailbreakr
My free book has a cover!
Work on lists of datasets instead of individual datasets by using functional programming
Method of Simulated Moments with R
New website!
Nonlinear Gmm with R - Example with a logistic regression
Simulated Maximum Likelihood with R
Bootstrapping standard errors for difference-in-differences estimation with R
Careful with tryCatch
Data frame columns as arguments to dplyr functions
Export R output to a file
I've started writing a 'book': Functional programming and unit testing for data munging with R
Introduction to programming econometrics with R
Merge a list of datasets together
Object Oriented Programming with R: An example with a Cournot duopoly
R, R with Atlas, R with OpenBLAS and Revolution R Open: which is fastest?
Read a lot of datasets at once with R
Unit testing with R
Update to Introduction to programming econometrics with R
Using R as a Computer Algebra System with Ryacas

End October I tweeted this:

will teach #rstats soon again but this time following @drob 's suggestion of the tidyverse first as laid out here: https://t.co/js8SsUs8Nv

— Bruno Rodrigues (@brodriguesco) October 24, 2017

and it generated some discussion. Some people believe that this is the right approach, and some
others think that one should first present *base* R and then show how the `tidyverse`

complements
it. This year, I taught three classes; a 12-hour class to colleagues that work with me, a 15-hour
class to master’s students and 3 hours again to some of my colleagues. Each time, I decided to
focus on the `tidyverse`

(almost) entirely, and must say that I am not disappointed with the results!

The 12 hour class was divided in two 6 hours days. It was a bit intense, especially the last 3 hours that took place Friday afternoon. The crowd was composed of some economists that had experience with STATA, some others that were mostly using Excel and finally some colleagues from the IT department that sometimes need to dig into some data themselves. Apart from 2 people, all the other never had any experience with R.

We went from 0 to being able to do the plot below after the end of the first day (so 6 hours in). Keep in mind that practically none of them even had opened RStudio before. I show the code so you can see the progress made in just a few hours:

```
library(Ecdat)
library(tidyverse)
library(ggthemes)
```

```
data(Bwages)
bwages = Bwages %>%
mutate(educ_level = case_when(educ == 1 ~ "Primary School",
educ == 2 ~ "High School",
educ == 3 ~ "Some university",
educ == 4 ~ "Master's degree",
educ == 5 ~ "Doctoral degree"))
ggplot(bwages) +
geom_smooth(aes(exper, wage, colour = educ_level)) +
theme_minimal() +
theme(legend.position = "bottom", legend.title = element_blank())
```

`## `geom_smooth()` using method = 'loess'`

Of course some of them needed some help here and there, and I also gave them hints (for example I told
them about `case_when()`

and try to use it inside `mutate()`

instead of nested ifs)
but it was mostly due to lack of experience and because they hadn’t had the time to fully digest
R’s syntax which was for most people involved completely new.

On the second day I showed `purrr::map()`

and `purrr::reduce()`

and overall it went quite well too.
I even showed list-columns, and this is where I started losing some of them; I did not insist too
much on it though, only wanted to show them the flexibility of `data.frame`

objects. Some of them
were quite impressed by list-columns! Then I started showing (for and while) loops and writing
functions. I even showed them `tidyeval`

and again, it went relatively well. Once they had the
opportunity to play a bit around with it, I think it clicked (plus they have lots of code examples
to go back too).

At the end, people seemed to have enjoyed the course, but told me that Friday was heavy; indeed it was, but I feel that it was mostly because 12 hours spread on 2 days is not the best format for this type of material, but we all had time constraints.

The 15 hour Master’s course was spread over 4 days, and covered basically the same. I just
used the last 3 hours to show the students some basic functions for model estimation
(linear, count, logit/probit and survival models). Again, the students were quite impressed by how
easily they could get descriptive statistics by first grouping by some variables. Through their
questions, I even got to show them scoped versions of `dplyr`

verbs, such as `select_if()`

and
`summarise_at()`

. I was expecting to lose them there, but actually most of them got these scoped
versions quite fast. These students already had some experience with R though, but none with
the `tidyverse`

.

Finally the 3 hour course was perhaps the most interesting; I only had 100% total beginners. Some
just knew R by name and had never heard/seen/opened RStudio (with the exception of one person)!
I did not show them any loops, function definitions and no plots. I only showed them how RStudio
looked and worked, what were (and how to install) packages (as well as the CRAN Task Views) and
then how to import data with `rio`

and do descriptive statistics only with `dplyr`

. They were
really interested and quite impressed by `rio`

(“what do you mean I can use the same code for
importing any dataset, in any format?”) but also by the simplicity of `dplyr`

.

In all the courses, I did show the `$`

primitive to refer to columns inside a `data.frame`

. First I
showed them lists which is where I introduced `$`

. Then it was easy to explain to them why it was
the same for a column inside a `data.frame`

; a `data.frame`

is simply a list! This is also the
distinction I made from the previous years; I simply mentioned (and showed really quickly) matrices
and focused almost entirely on lists. Most participants, if not all, had learned to program
statistics by thinking about linear algebra and matrices. Nothing wrong with that, but I feel that R
really shines when you focus on lists and on how to work with them.

Overall as the teacher, I think that focusing on the `tidyverse`

might be a very good strategy. I
might have to do some adjustments here and there for the future courses, but my hunch is that the
difficulties that some participants had were not necessarily due to the `tidyverse`

but simply to
lack of time to digest what was shown, as well as a total lack of experience with R.
I do not think that these participants would have better understood a more traditional, `base`

,
matrix-oriented course.