Importance of preallocation

Lots of people forget to do this on the World Bank data importing exercise. Any way to better explain this? I already have a similar graph, but this is another good example

library(tidyverse)
library(microbenchmark)

# bind together 100 copies of mpg
times <- microbenchmark(
  `No preallocation` = {
    mpg_no_preall <- tibble()

    for(i in 1:100){
      mpg_no_preall <- bind_rows(mpg_no_preall, mpg)
    }
  },
  `Preallocation` = {
    mpg_preall <- vector(mode = "list", length = 100)

    for(i in 1:100){
      mpg_preall[[i]] <- mpg
    }

    mpg_preall <- bind_rows(mpg_preall)
  }
)

autoplot(times)
#> Coordinate system already present. Adding new coordinate system, which will replace the existing one.

^{Created on 2020-07-10 by the reprex package (v0.3.0)}

Session info

``` r devtools::session_info() #> ─ Session info ─────────────────────────────────────────────────────────────── #> setting value #> version R version 4.0.1 (2020-06-06) #> os macOS Catalina 10.15.5 #> system x86_64, darwin17.0 #> ui X11 #> language (EN) #> collate en_US.UTF-8 #> ctype en_US.UTF-8 #> tz America/Chicago #> date 2020-07-10 #> #> ─ Packages ─────────────────────────────────────────────────────────────────── #> package * version date lib source #> assertthat 0.2.1 2019-03-21 [1] CRAN (R 4.0.0) #> backports 1.1.7 2020-05-13 [1] CRAN (R 4.0.0) #> blob 1.2.1 2020-01-20 [1] CRAN (R 4.0.0) #> broom 0.5.6 2020-04-20 [1] CRAN (R 4.0.0) #> callr 3.4.3 2020-03-28 [1] CRAN (R 4.0.0) #> cellranger 1.1.0 2016-07-27 [1] CRAN (R 4.0.0) #> cli 2.0.2 2020-02-28 [1] CRAN (R 4.0.0) #> colorspace 1.4-1 2019-03-18 [1] CRAN (R 4.0.0) #> crayon 1.3.4 2017-09-16 [1] CRAN (R 4.0.0) #> curl 4.3 2019-12-02 [1] CRAN (R 4.0.0) #> DBI 1.1.0 2019-12-15 [1] CRAN (R 4.0.0) #> dbplyr 1.4.4 2020-05-27 [1] CRAN (R 4.0.0) #> desc 1.2.0 2018-05-01 [1] CRAN (R 4.0.0) #> devtools 2.3.0 2020-04-10 [1] CRAN (R 4.0.0) #> digest 0.6.25 2020-02-23 [1] CRAN (R 4.0.0) #> dplyr * 1.0.0 2020-05-29 [1] CRAN (R 4.0.0) #> 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) #> fansi 0.4.1 2020-01-08 [1] CRAN (R 4.0.0) #> farver 2.0.3 2020-01-16 [1] CRAN (R 4.0.0) #> forcats * 0.5.0 2020-03-01 [1] CRAN (R 4.0.0) #> fs 1.4.1 2020-04-04 [1] CRAN (R 4.0.0) #> generics 0.0.2 2018-11-29 [1] CRAN (R 4.0.0) #> ggplot2 * 3.3.1 2020-05-28 [1] CRAN (R 4.0.0) #> glue 1.4.1 2020-05-13 [1] CRAN (R 4.0.0) #> 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 0.5.3 2020-01-08 [1] CRAN (R 4.0.0) #> htmltools 0.4.0 2019-10-04 [1] CRAN (R 4.0.0) #> httr 1.4.1 2019-08-05 [1] CRAN (R 4.0.0) #> jsonlite 1.6.1 2020-02-02 [1] CRAN (R 4.0.0) #> knitr 1.28 2020-02-06 [1] CRAN (R 4.0.0) #> lattice 0.20-41 2020-04-02 [1] CRAN (R 4.0.0) #> lifecycle 0.2.0 2020-03-06 [1] CRAN (R 4.0.0) #> lubridate 1.7.8 2020-04-06 [1] CRAN (R 4.0.0) #> magrittr 1.5 2014-11-22 [1] CRAN (R 4.0.0) #> memoise 1.1.0 2017-04-21 [1] CRAN (R 4.0.0) #> microbenchmark * 1.4-7 2019-09-24 [1] CRAN (R 4.0.0) #> mime 0.9 2020-02-04 [1] CRAN (R 4.0.0) #> 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) #> nlme 3.1-148 2020-05-24 [1] CRAN (R 4.0.0) #> pillar 1.4.4 2020-05-05 [1] CRAN (R 4.0.0) #> pkgbuild 1.0.8 2020-05-07 [1] CRAN (R 4.0.0) #> 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 3.4.2 2020-02-09 [1] CRAN (R 4.0.0) #> ps 1.3.3 2020-05-08 [1] CRAN (R 4.0.0) #> purrr * 0.3.4 2020-04-17 [1] CRAN (R 4.0.0) #> R6 2.4.1 2019-11-12 [1] CRAN (R 4.0.0) #> Rcpp 1.0.4.6 2020-04-09 [1] CRAN (R 4.0.0) #> readr * 1.3.1 2018-12-21 [1] CRAN (R 4.0.0) #> readxl 1.3.1 2019-03-13 [1] CRAN (R 4.0.0) #> remotes 2.1.1 2020-02-15 [1] CRAN (R 4.0.0) #> reprex 0.3.0 2019-05-16 [1] CRAN (R 4.0.0) #> rlang 0.4.6.9000 2020-06-08 [1] Github (r-lib/rlang@10b32e8) #> rmarkdown 2.2 2020-05-31 [1] CRAN (R 4.0.0) #> rprojroot 1.3-2 2018-01-03 [1] CRAN (R 4.0.0) #> rvest 0.3.5 2019-11-08 [1] CRAN (R 4.0.0) #> 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 1.4.6 2020-02-17 [1] CRAN (R 4.0.0) #> stringr * 1.4.0 2019-02-10 [1] CRAN (R 4.0.0) #> testthat 2.3.2 2020-03-02 [1] CRAN (R 4.0.0) #> tibble * 3.0.1 2020-04-20 [1] CRAN (R 4.0.0) #> tidyr * 1.1.0 2020-05-20 [1] CRAN (R 4.0.0) #> 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 1.6.1 2020-04-29 [1] CRAN (R 4.0.0) #> vctrs 0.3.1 2020-06-05 [1] CRAN (R 4.0.1) #> withr 2.2.0 2020-04-20 [1] CRAN (R 4.0.0) #> xfun 0.14 2020-05-20 [1] CRAN (R 4.0.0) #> 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] /Library/Frameworks/R.framework/Versions/4.0/Resources/library ```

cis-ds / course-site

Importance of preallocation #248