  Jennifer Bryan 
 RStudio, University of British Columbia @JennyBryan @jennybc bit.ly/jenny-earl Go here for useful links to stuff mentioned in this talk!!

workflow you should have one

‑decision fatigue ‑unique and special ❆❄❅ ‐ predictability ‐ proficiency ‐ access to help

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Here’s my highly polished blog post about deep learning. Here’s how I organized the files and wrangled the data.

Import Tidy Communicate Transform Visualise Model

Import Tidy Communicate Transform Visualise Model

Everything that exists in R is an object. Everything that happens in R is a function call. Interfaces to other software are part of R. — John Chambers

Import Tidy Communicate Transform Visualise Model

Import Tidy Communicate Transform Visualise Model

http://readxl.tidyverse.org readxl www.rstudio.com

http://googledrive.tidyverse.org

googlesheets + googledrive googlesheets4 =

What is your development environment? How do you organize a project? How do you manage a project over time? What about collaboration?

What is your default data receptacle? How do you manipulate data? How do you iterate?

http://stat545.com

Good enough practices in scientific computing Wilson, Bryan, Cranston, Kitzes, Nederbragt, Teal https://doi.org/10.1371/journal.pcbi.1005510 http://bit.ly/good-enuff

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Excuse me, do you have a moment to talk about version control? https://doi.org/10.7287/peerj.preprints.3159v2

happygitwithr.com

http://reprex.tidyverse.org

workflow example #1

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One folder per project That folder is an • RStudio Project (package? website? whatever) • Git repo, with associated GitHub remote Work on multiple projects at once w/ multiple instances of RStudio • Each gets own child R process • R & file browser have sane working directory

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If the first line of your #rstats script is setwd("C:\Users\jenny\path\that\only\I\have"), I will come into your lab and SET YOUR COMPUTER ON FIRE . — Mash-up of rage tweets by @jennybc and @tpoi.

Use here package to build paths within a Project Paths are robust to different working directories within the Project • Render .R and .Rmd that live in sub-folders! • Write paths in tests and vignettes w/o fear! here wraps the more powerful rprojroot package

library(here) #> here() starts at /here-demo system("tree") #> . #> !"" one #> !"" two #> !"" awesome.txt here("one", "two", "awesome.txt") #> [1] "/here-demo/one/two/awesome.txt" cat(readLines(here("one", "two", "awesome.txt"))) #> OMG this is so awesome! setwd(here("one")) getwd() #> [1] "/here-demo/one" here("one", "two", "awesome.txt") #> [1] "/here-demo/one/two/awesome.txt” cat(readLines(here("one", "two", "awesome.txt"))) #> OMG this is so awesome!

workflow example #2

list-columns EmbRAce tHe aWkwArd

#rstats lists via lego

map(.x, .f, ...) purrr::

map(.x, .f, ...) for every element of .x apply .f

.x = minis

map(minis, antennate)

.x = minis

map(minis, "pants")

.y = hair .x = minis

map2(minis, hair, enhair)

.y = weapons .x = minis

map2(minis, weapons, arm)

minis %>% map2(hair, enhair) %>% map2(weapons, arm)

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this is a data frame! atomic vector list column

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data frame nested data frame

gap_nested <- gapminder %>%
 group_by(country) %>%
 nest()
 gap_nested
 #> # A tibble: 142 × 2
 #> country data
 #> 
 #> 1 Afghanistan 
 #> 2 Albania 
 #> 3 Algeria 
 #> 4 Angola 
 #> 5 Argentina 
 #> 6 Australia 
 #> 7 Austria 
 #> 8 Bahrain 
 #> 9 Bangladesh 
 #> 10 Belgium 
 #> # ... with 132 more rows

gap_fits <- gap_nested %>%
 mutate(fit = map(data, ~ lm(lifeExp ~ year, data = .x)))
 
 gap_fits %>% tail(3)
 #> # A tibble: 3 × 3
 #> country data fit
 #> 
 #> 1 Yemen, Rep. 
 #> 2 Zambia 
 #> 3 Zimbabwe 
 canada <- which(gap_fits$country == "Canada")
 summary(gap_fits$fit[[canada]])
 #> . . .
 #> Coefficients:
 #> Estimate Std. Error t value Pr(>|t|) 
 #> (Intercept) -3.583e+02 8.252e+00 -43.42 1.01e-12 ***
 #> year 2.189e-01 4.169e-03 52.50 1.52e-13 ***
 #> . . . 
 #> Residual standard error: 0.2492 on 10 degrees of freedom
 #> Multiple R-squared: 0.9964, Adjusted R-squared: 0.996 
 #> F-statistic: 2757 on 1 and 10 DF, p-value: 1.521e-1

gap_fits %>%
 mutate(rsq = map_dbl(fit, ~ summary(.x)[["r.squared"]])) %>%
 arrange(rsq)
 #> # A tibble: 142 × 4
 #> country data fit rsq
 #> 
 #> 1 Rwanda 0.01715964
 #> 2 Botswana 0.03402340
 #> 3 Zimbabwe 0.05623196
 #> 4 Zambia 0.05983644
 #> 5 Swaziland 0.06821087
 #> 6 Lesotho 0.08485635
 #> 7 Cote d'Ivoire 0.28337240
 #> 8 South Africa 0.31246865
 #> 9 Uganda 0.34215382
 #> 10 Congo, Dem. Rep. 0.34820278
 #> # ... with 132 more rows

gap_fits %>%
 mutate(coef = map(fit, broom::tidy)) %>%
 unnest(coef)
 #> # A tibble: 284 × 6
 #> country term estimate std.error statistic
 #> 
 #> 1 Afghanistan (Intercept) -507.5342716 40.484161954 -12.536613
 #> 2 Afghanistan year 0.2753287 0.020450934 13.462890
 #> 3 Albania (Intercept) -594.0725110 65.655359062 -9.048348
 #> 4 Albania year 0.3346832 0.033166387 10.091036
 #> 5 Algeria (Intercept) -1067.8590396 43.802200843 -24.379118
 #> 6 Algeria year 0.5692797 0.022127070 25.727749
 #> 7 Angola (Intercept) -376.5047531 46.583370599 -8.082385
 #> 8 Angola year 0.2093399 0.023532003 8.895964
 #> 9 Argentina (Intercept) -389.6063445 9.677729641 -40.258031
 #> 10 Argentina year 0.2317084 0.004888791 47.395847
 #> # ... with 274 more rows, and 1 more variables: p.value

maybe you don’t, because it’s too painful for loops apply(), [slvmt]apply(), split(), by() with plyr: [adl][adl_]ply() with dplyr: df %>% group_by() %>% do() How do you do such things today?

Many other worked examples here: https://jennybc.github.io/purrr-tutorial/

@JennyBryan @jennybc   bit.ly/jenny-earl