rstudio::conf 2019

Shortcuts

Coming into rstudio::conf I had a few keyboard shortcuts memorized. Things like copying a line of code down (CMD + SHIFT + DOWN ARROW) … inserting the pipe operator (CMD + SHIFT + M) … and inserting a code chunk (CMD + OPTION + I).

But there are so many more … a few handy ones that I picked up:

• Maximize an Rstudio pane: SHIFT + CTRL + 1 (1,2,3,4 for each pane clockwise)
• Build a package: SHIFT + CMD + B
• Load functions from package after building: SHIFT + CMD + L

My friends (and fellow Charlottesville R Users) Jeff Boichuk and Steve Mortimer have also developed an R package (CrossR) that includes a data frame with all Rstudio shortcuts:

devtools::install_github("jeffboichuk/CrossR")
library(CrossR)

shortcuts

## # A tibble: 122 x 4
##    category description        mac             windows         
##    <chr>    <chr>              <chr>           <chr>           
##  1 Build    Build All          Shift + Cmd + B Ctrl + Shift + B
##  2 Build    Check Package      Shift + Cmd + E Ctrl + Shift + E
##  3 Build    Compile PDF        Shift + Cmd + K Ctrl + Shift + K
##  4 Build    Devtools Load All  Shift + Cmd + L Ctrl + Shift + L
##  5 Build    Knit Document      Shift + Cmd + K Ctrl + Shift + K
##  6 Build    Preview HTML       Shift + Cmd + K Ctrl + Shift + K
##  7 Build    Roxygenize Package Shift + Cmd + D Ctrl + Shift + D
##  8 Build    Test Package       Shift + Cmd + T Ctrl + Shift + T
##  9 Console  Console Clear      Ctrl + L        Ctrl + L        
## 10 Debug    Debug Breakpoint   Shift + F9      Shift + F9      
## # … with 112 more rows

find_shortcuts("roxygen")

## # A tibble: 2 x 3
##   category      description             mac                  
##   <chr>         <chr>                   <chr>                
## 1 Build         Roxygenize Package      Shift + Cmd + D      
## 2 Source Editor Insert Roxygen Skeleton Shift + Alt + Cmd + R

RStudio 1.2 features

The RStudio team is working to make the RStudio IDE an even more comprehensive data science toolkit. Version 1.2 introduces features to support multiple languages, including python, SQL and D3. Jonathan McPherson gave a tour of the new multilingual support:

https://resources.rstudio.com/rstudio-conf-2019/new-language-features-in-rstudio

I put together a trivial example of what this looks workflow looks like for passing R objects to python (and vice versa) from chunk-to-chunk in an R markdown document:

```{r setup}
  library(reticulate)
  use_python("/usr/bin/python", required = TRUE)
```

```{python}
  import random
  x = random.randint(1,99)
  print x
```

```{r}
  # access the object 'x' from python environment with py$x
  py$x

  y <- py$x^2

  y
```

```{python}
  # access the object 'y' from r environment with r.y
  print r.y

  import math
  z = math.sqrt(r.y)

  print z
```

For a more complete example (including D3 and SQL chunks), take a look at the spenders.Rmd example:

https://github.com/jmcphers/rstudio-1.2-features/blob/master/spenders.Rmd

New language features in RStudio - Jonathan McPherson

Tidy eval

Programming with tidy eval can seem daunting. One of the sessions of the Building Tidy Tools workshop focused on tidy eval. That talk demystified the quoting/unquoting workflow. Maybe more importantly for me, I found out that Rstudio is compiling a list of use-cases/examples of tidy eval in the wild:

https://community.rstudio.com/t/interesting-tidy-eval-use-cases/21121

Working with names and expressions in your tidy eval code - Lionel Henry

separate_rows()

The tidyr separate_rows() function isn’t a new by any means, but it’s one that I picked up during a demo at the conference. This will be for handy “wide-to-long” transformations on data that is packed into a single column (and separated by a common delimiter):

library(tidyr)


dat <-
  data.frame(
    id = 1:5,
    diagnosis = c(NA, "A,B,C", "D", "B,E,F", "A")
  )

dat

##   id diagnosis
## 1  1      <NA>
## 2  2     A,B,C
## 3  3         D
## 4  4     B,E,F
## 5  5         A

separate_rows(dat, diagnosis, sep = ",")

##   id diagnosis
## 1  1      <NA>
## 2  2         A
## 3  2         B
## 4  2         C
## 5  3         D
## 6  4         B
## 7  4         E
## 8  4         F
## 9  5         A

.Rmd to .pptx

Again … not a new feature, but new to me:

https://bookdown.org/yihui/rmarkdown/powerpoint-presentation.html

You can convert R markdown to PowerPoint by specifying powerpoint_presentation as the output format in the YAML header:

---
title: "Figs"
author: "VP Nagraj"
date: "3/10/2019"
output: powerpoint_presentation
---

nb this output format requires Pandoc 2.x

New packages

There were a ton of new (or at least new-ish) packages introduced at rstudio::conf.