workshop_description.org

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#+PROPERTY: header-args:R :session R:ioc :results output :exports code :tangle yes :comments link :eval no

#+TITLE:   Better practices in R,@@html:<br>@@no more copy-paste, no more loops
#+DATE:	   {{{time(%B %d\, %Y)}}}
#+AUTHOR:  Marie-Hélène Burle
#+EMAIL:   msb2@sfu.ca

* Goal

Code more efficiently and develop better R practices: replace repetitions, loops, and lengthy code prone to error by clean functions using the package @@html:<span style="padding: 0em 0.2em 0em 0.2em; color: #000000; background-color: #f9b9b9; border-radius: 3px">@@purrr@@html:</span>@@. Purrr is the tidyverse equivalent to the src_R[:eval no]{apply()} functions, but it has more tools and it is more consistent.

** Example

#+BEGIN_VERBATIM
Create a named vector with the maximum values of all the variables in the mtcars dataset.
#+END_VERBATIM

#+BEGIN_VERSE
Copy-paste method:
#+END_VERSE

Don't do this! It is a hard-coding practice prone to error. Not to mention, very tedious...

#+BEGIN_SRC R
setNames(
  c(max(mtcars[1]),
    max(mtcars[2]),
    max(mtcars[3]),
    max(mtcars[4]),
    max(mtcars[5]),
    max(mtcars[6]),
    max(mtcars[7]),
    max(mtcars[8]),
    max(mtcars[9]),
    max(mtcars[10]),
    max(mtcars[11])
    ),
  names(mtcars)
)
#+END_SRC

#+BEGIN_VERSE
For loop method:
#+END_VERSE

#+BEGIN_SRC R
max <- vector("double", ncol(mtcars))

for (i in seq_along(mtcars)) {
  max[[i]] <- max(mtcars[[i]])
}

setNames(max, names(mtcars))
#+END_SRC

#+BEGIN_VERSE
Purrr method (yeah!):
#+END_VERSE

#+BEGIN_SRC R
map_dbl(mtcars, max)
#+END_SRC

* Target audience

- Intermediate R users comfortable with basic data manipulation and simple functions, or
- Advanced users familiar with functional programming using the src_R[:eval no]{apply()} functions family and interested in discovering the "purrring" way.

* Program

- Quick tips for better reproducibility, portability, and code readability,
- Introduction to functional programming with the tidyverse package purrr.

For more information, please visit the [[https://prosoitos.github.io/International-Ornithological-Congress_r-workshops/][workshop webpage]].

* Software requirements

In order to make the best of this workshop, please bring a laptop with the following installed:

- the *latest* R version (if you usually run R in RStudio, make sure that you also have the latest RStudio),
- the *latest* version of the tidyverse package,
- the *latest* version of the patchwork package.

At the time of this writing, the patchwork package is not yet on CRAN and can be installed by running:

#+BEGIN_SRC R
install.packages("devtools")                      # if you haven't installed it already
devtools::install_github("thomasp85/patchwork")
#+END_SRC

No data file is needed for this workshop.

Please make sure everything is running before coming. Thank you and see you there!

#+HTML: <br>

------------------------------
/Contact: Marie-Helene Burle, msb2@sfu.ca/