Plotting multiple plots using purrr::map and ggplot

1 Load packages

library(tidyverse)  # data wrangling

2 Sample data

mtcars to the rescue!

data(mtcars)

3 Motivation

Say we have a data frame where we would like to plot each numeric variables’s distribution.

There are a number of good solutions outthere such as this one, or here, or here.

4 Way 1

mtcars %>% 
  select(where(is.numeric)) %>% 
  map( ~ {ggplot(mtcars, aes(x = .)) + geom_density()}
  )

Note that the chunks options above were like this:

{r fig.show="hold", out.width="30%", results = "hide"}

Works. But does not show the variable names. Next try.

5 Way 2

dens_fun <- function(var, name) {
  
  ggplot(mtcars, aes(x = var)) +
    geom_density() +
    labs(x = name,
         title = name)
}

mtcars %>% 
  select(where(is.numeric)) %>% 
  map2(.y = names(.),
       ~ dens_fun(.x, .y)
  )

6 Reproducibility

#> ─ Session info ───────────────────────────────────────────────────────────────────────────────────────────────────────
#>  setting  value                       
#>  version  R version 4.0.2 (2020-06-22)
#>  os       macOS  10.16                
#>  system   x86_64, darwin17.0          
#>  ui       X11                         
#>  language (EN)                        
#>  collate  en_US.UTF-8                 
#>  ctype    en_US.UTF-8                 
#>  tz       Europe/Berlin               
#>  date     2021-02-06                  
#> 
#> ─ Packages ───────────────────────────────────────────────────────────────────────────────────────────────────────────
#>  package     * version     date       lib source                             
#>  assertthat    0.2.1       2019-03-21 [1] CRAN (R 4.0.0)                     
#>  backports     1.2.1       2020-12-09 [1] CRAN (R 4.0.2)                     
#>  blogdown      1.1         2021-01-19 [1] CRAN (R 4.0.2)                     
#>  bookdown      0.21.6      2021-02-02 [1] Github (rstudio/bookdown@6c7346a)  
#>  broom         0.7.4       2021-01-29 [1] CRAN (R 4.0.2)                     
#>  bslib         0.2.4.9000  2021-02-02 [1] Github (rstudio/bslib@b3cd7a9)     
#>  cachem        1.0.1       2021-01-21 [1] CRAN (R 4.0.2)                     
#>  callr         3.5.1       2020-10-13 [1] CRAN (R 4.0.2)                     
#>  cellranger    1.1.0       2016-07-27 [1] CRAN (R 4.0.0)                     
#>  cli           2.3.0       2021-01-31 [1] CRAN (R 4.0.2)                     
#>  codetools     0.2-16      2018-12-24 [2] CRAN (R 4.0.2)                     
#>  colorspace    2.0-0       2020-11-11 [1] CRAN (R 4.0.2)                     
#>  crayon        1.4.0       2021-01-30 [1] CRAN (R 4.0.2)                     
#>  DBI           1.1.1       2021-01-15 [1] CRAN (R 4.0.2)                     
#>  dbplyr        2.0.0       2020-11-03 [1] CRAN (R 4.0.2)                     
#>  desc          1.2.0       2018-05-01 [1] CRAN (R 4.0.0)                     
#>  devtools      2.3.2       2020-09-18 [1] CRAN (R 4.0.2)                     
#>  digest        0.6.27      2020-10-24 [1] CRAN (R 4.0.2)                     
#>  dplyr       * 1.0.3       2021-01-15 [1] CRAN (R 4.0.2)                     
#>  ellipsis      0.3.1       2020-05-15 [1] CRAN (R 4.0.0)                     
#>  evaluate      0.14        2019-05-28 [1] CRAN (R 4.0.0)                     
#>  farver        2.0.3       2020-01-16 [1] CRAN (R 4.0.0)                     
#>  fastmap       1.1.0       2021-01-25 [1] CRAN (R 4.0.2)                     
#>  forcats     * 0.5.1       2021-01-27 [1] CRAN (R 4.0.2)                     
#>  fs            1.5.0       2020-07-31 [1] CRAN (R 4.0.2)                     
#>  generics      0.1.0       2020-10-31 [1] CRAN (R 4.0.2)                     
#>  ggplot2     * 3.3.3       2020-12-30 [1] CRAN (R 4.0.2)                     
#>  glue          1.4.2       2020-08-27 [1] CRAN (R 4.0.2)                     
#>  gtable        0.3.0       2019-03-25 [1] CRAN (R 4.0.0)                     
#>  haven         2.3.1       2020-06-01 [1] CRAN (R 4.0.0)                     
#>  highr         0.8         2019-03-20 [1] CRAN (R 4.0.0)                     
#>  hms           1.0.0       2021-01-13 [1] CRAN (R 4.0.2)                     
#>  htmltools     0.5.1.1     2021-01-22 [1] CRAN (R 4.0.2)                     
#>  httr          1.4.2       2020-07-20 [1] CRAN (R 4.0.2)                     
#>  jquerylib     0.1.3       2020-12-17 [1] CRAN (R 4.0.2)                     
#>  jsonlite      1.7.2       2020-12-09 [1] CRAN (R 4.0.2)                     
#>  knitr         1.31        2021-01-27 [1] CRAN (R 4.0.2)                     
#>  labeling      0.4.2       2020-10-20 [1] CRAN (R 4.0.2)                     
#>  lifecycle     0.2.0       2020-03-06 [1] CRAN (R 4.0.0)                     
#>  lubridate     1.7.9.2     2020-11-13 [1] CRAN (R 4.0.2)                     
#>  magrittr      2.0.1       2020-11-17 [1] CRAN (R 4.0.2)                     
#>  memoise       2.0.0       2021-01-26 [1] CRAN (R 4.0.2)                     
#>  modelr        0.1.8       2020-05-19 [1] CRAN (R 4.0.0)                     
#>  munsell       0.5.0       2018-06-12 [1] CRAN (R 4.0.0)                     
#>  pillar        1.4.7       2020-11-20 [1] CRAN (R 4.0.2)                     
#>  pkgbuild      1.2.0       2020-12-15 [1] CRAN (R 4.0.2)                     
#>  pkgconfig     2.0.3       2019-09-22 [1] CRAN (R 4.0.0)                     
#>  pkgload       1.1.0       2020-05-29 [1] CRAN (R 4.0.0)                     
#>  prettyunits   1.1.1       2020-01-24 [1] CRAN (R 4.0.0)                     
#>  processx      3.4.5       2020-11-30 [1] CRAN (R 4.0.2)                     
#>  ps            1.5.0       2020-12-05 [1] CRAN (R 4.0.2)                     
#>  purrr       * 0.3.4       2020-04-17 [1] CRAN (R 4.0.0)                     
#>  R6            2.5.0       2020-10-28 [1] CRAN (R 4.0.2)                     
#>  Rcpp          1.0.6       2021-01-15 [1] CRAN (R 4.0.2)                     
#>  readr       * 1.4.0       2020-10-05 [1] CRAN (R 4.0.2)                     
#>  readxl        1.3.1       2019-03-13 [1] CRAN (R 4.0.0)                     
#>  remotes       2.2.0       2020-07-21 [1] CRAN (R 4.0.2)                     
#>  reprex        1.0.0       2021-01-27 [1] CRAN (R 4.0.2)                     
#>  rlang         0.4.10      2020-12-30 [1] CRAN (R 4.0.2)                     
#>  rmarkdown     2.6.6       2021-02-05 [1] Github (rstudio/rmarkdown@6566366) 
#>  rprojroot     2.0.2       2020-11-15 [1] CRAN (R 4.0.2)                     
#>  rstudioapi    0.13.0-9000 2020-12-09 [1] Github (rstudio/rstudioapi@4baeb39)
#>  rvest         0.3.6       2020-07-25 [1] CRAN (R 4.0.2)                     
#>  sass          0.3.1       2021-01-24 [1] CRAN (R 4.0.2)                     
#>  scales        1.1.1       2020-05-11 [1] CRAN (R 4.0.0)                     
#>  sessioninfo   1.1.1       2018-11-05 [1] CRAN (R 4.0.0)                     
#>  stringi       1.5.3       2020-09-09 [1] CRAN (R 4.0.2)                     
#>  stringr     * 1.4.0       2019-02-10 [1] CRAN (R 4.0.0)                     
#>  testthat      3.0.1       2020-12-17 [1] CRAN (R 4.0.2)                     
#>  tibble      * 3.0.6       2021-01-29 [1] CRAN (R 4.0.2)                     
#>  tidyr       * 1.1.2       2020-08-27 [1] CRAN (R 4.0.2)                     
#>  tidyselect    1.1.0       2020-05-11 [1] CRAN (R 4.0.0)                     
#>  tidyverse   * 1.3.0       2019-11-21 [1] CRAN (R 4.0.0)                     
#>  usethis       2.0.0       2020-12-10 [1] CRAN (R 4.0.2)                     
#>  vctrs         0.3.6       2020-12-17 [1] CRAN (R 4.0.2)                     
#>  withr         2.4.1       2021-01-26 [1] CRAN (R 4.0.2)                     
#>  xfun          0.20        2021-01-06 [1] CRAN (R 4.0.2)                     
#>  xml2          1.3.2       2020-04-23 [1] CRAN (R 4.0.0)                     
#>  yaml          2.2.1       2020-02-01 [1] CRAN (R 4.0.0)                     
#> 
#> [1] /Users/sebastiansaueruser/Rlibs
#> [2] /Library/Frameworks/R.framework/Versions/4.0/Resources/library