library(magrittr)
library(tibble)
library(tidyr)
#>
#> Attaching package: 'tidyr'
#> The following object is masked from 'package:magrittr':
#>
#> extract
library(dplyr)
#>
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#>
#> filter, lag
#> The following objects are masked from 'package:base':
#>
#> intersect, setdiff, setequal, union
# Proper nesting of cyl using group_by
df1 <- mtcars %>%
group_by(cyl) %>%
nest()
df1
#> # A tibble: 3 x 2
#> cyl data
#> <dbl> <list>
#> 1 6 <tibble [7 × 10]>
#> 2 4 <tibble [11 × 10]>
#> 3 8 <tibble [14 × 10]>
names(df1$data[[1]])
#> [1] "mpg" "disp" "hp" "drat" "wt" "qsec" "vs" "am" "gear" "carb"
# Proper nesting of cyl using nest alone
df2 <- as_tibble(mtcars) %>%
nest(-cyl)
df2
#> # A tibble: 3 x 2
#> cyl data
#> <dbl> <list>
#> 1 6 <tibble [7 × 10]>
#> 2 4 <tibble [11 × 10]>
#> 3 8 <tibble [14 × 10]>
names(df2$data[[1]])
#> [1] "mpg" "disp" "hp" "drat" "wt" "qsec" "vs" "am" "gear" "carb"
# Now assume you did a group_by and forgot to
# ungroup and then wanted to nest on gear
df3 <- mtcars %>%
group_by(cyl) %>%
#mutate(cyl_index = 1:n()) %>%
nest(-gear)
df3
#> # A tibble: 3 x 2
#> cyl data
#> <dbl> <list>
#> 1 6 <tibble [7 × 9]>
#> 2 4 <tibble [11 × 9]>
#> 3 8 <tibble [14 × 9]>
names(df3$data[[1]])
#> [1] "mpg" "disp" "hp" "drat" "wt" "qsec" "vs" "am" "carb"
# In this case the group_by supersedes the nest argument.
# That's not much of a problem
# The problem is gear is now dropped from the nested data.frameCreated on 2019-01-30 by the reprex package (v0.2.1)
Session info
devtools::session_info()
#> ─ Session info ──────────────────────────────────────────────────────────
#> setting value
#> version R version 3.5.2 (2018-12-20)
#> os macOS Mojave 10.14.3
#> system x86_64, darwin15.6.0
#> ui X11
#> language (EN)
#> collate en_US.UTF-8
#> ctype en_US.UTF-8
#> tz America/Denver
#> date 2019-01-30
#>
#> ─ Packages ──────────────────────────────────────────────────────────────
#> package * version date lib source
#> assertthat 0.2.0 2017-04-11 [1] CRAN (R 3.5.0)
#> backports 1.1.3 2018-12-14 [1] CRAN (R 3.5.0)
#> bindr 0.1.1 2018-03-13 [1] CRAN (R 3.5.0)
#> bindrcpp * 0.2.2 2018-03-29 [1] CRAN (R 3.5.0)
#> callr 3.1.1 2018-12-21 [1] CRAN (R 3.5.0)
#> cli 1.0.1 2018-09-25 [1] CRAN (R 3.5.0)
#> crayon 1.3.4 2017-09-16 [1] CRAN (R 3.5.0)
#> desc 1.2.0 2018-05-01 [1] CRAN (R 3.5.0)
#> devtools 2.0.1 2018-10-26 [1] CRAN (R 3.5.1)
#> digest 0.6.18 2018-10-10 [1] CRAN (R 3.5.0)
#> dplyr * 0.7.8 2018-11-10 [1] CRAN (R 3.5.0)
#> evaluate 0.12 2018-10-09 [1] CRAN (R 3.5.0)
#> fansi 0.4.0 2018-10-05 [1] CRAN (R 3.5.0)
#> fs 1.2.6 2018-08-23 [1] CRAN (R 3.5.0)
#> glue 1.3.0 2018-07-17 [1] CRAN (R 3.5.0)
#> highr 0.7 2018-06-09 [1] CRAN (R 3.5.0)
#> htmltools 0.3.6 2017-04-28 [1] CRAN (R 3.5.0)
#> knitr 1.21 2018-12-10 [1] CRAN (R 3.5.1)
#> magrittr * 1.5 2014-11-22 [1] CRAN (R 3.5.0)
#> memoise 1.1.0 2017-04-21 [1] CRAN (R 3.5.0)
#> pillar 1.3.1 2018-12-15 [1] CRAN (R 3.5.0)
#> pkgbuild 1.0.2 2018-10-16 [1] CRAN (R 3.5.0)
#> pkgconfig 2.0.2 2018-08-16 [1] CRAN (R 3.5.0)
#> pkgload 1.0.2 2018-10-29 [1] CRAN (R 3.5.0)
#> prettyunits 1.0.2 2015-07-13 [1] CRAN (R 3.5.0)
#> processx 3.2.1 2018-12-05 [1] CRAN (R 3.5.0)
#> ps 1.3.0 2018-12-21 [1] CRAN (R 3.5.0)
#> purrr 0.2.5 2018-05-29 [1] CRAN (R 3.5.0)
#> R6 2.3.0 2018-10-04 [1] CRAN (R 3.5.0)
#> Rcpp 1.0.0 2018-11-07 [1] CRAN (R 3.5.0)
#> remotes 2.0.2 2018-10-30 [1] CRAN (R 3.5.0)
#> rlang 0.3.1 2019-01-08 [1] CRAN (R 3.5.2)
#> rmarkdown 1.11 2018-12-08 [1] CRAN (R 3.5.0)
#> rprojroot 1.3-2 2018-01-03 [1] CRAN (R 3.5.0)
#> sessioninfo 1.1.1 2018-11-05 [1] CRAN (R 3.5.0)
#> stringi 1.2.4 2018-07-20 [1] CRAN (R 3.5.0)
#> stringr 1.3.1 2018-05-10 [1] CRAN (R 3.5.0)
#> testthat 2.0.1 2018-10-13 [1] CRAN (R 3.5.0)
#> tibble * 2.0.1 2019-01-12 [1] CRAN (R 3.5.2)
#> tidyr * 0.8.2 2018-10-28 [1] CRAN (R 3.5.0)
#> tidyselect 0.2.5 2018-10-11 [1] CRAN (R 3.5.0)
#> usethis 1.4.0 2018-08-14 [1] CRAN (R 3.5.0)
#> utf8 1.1.4 2018-05-24 [1] CRAN (R 3.5.0)
#> withr 2.1.2 2018-03-15 [1] CRAN (R 3.5.0)
#> xfun 0.4 2018-10-23 [1] CRAN (R 3.5.0)
#> yaml 2.2.0 2018-07-25 [1] CRAN (R 3.5.0)
#>
#> [1] /Users/sfield/r_libs
#> [2] /Library/Frameworks/R.framework/Versions/3.5/Resources/library