Experimenting with yet another way to do rowwise operations.
You can install rap
from gitub
# install.packages("devtools")
devtools::install_github("romainfrancois/rap")
This offers rap()
as an alternative to some versions of:
rowwise()
+ do()
mutate()
+ pmap()
purrrlyr
?rap()
works with lambdas supplied as formulas, similar to purrr::map()
but instead of .x
, .y
, ..1
, ..2
, ...the lambda can use the column names, which stand for a single element of the associated vector, in the [[
sense.
library(tidyverse)
#> ── Attaching packages ──────────────────── tidyverse 1.2.1 ──
#> ✔ ggplot2 3.1.0 ✔ purrr 0.2.5.9000
#> ✔ tibble 1.4.99.9006 ✔ dplyr 0.7.8
#> ✔ tidyr 0.8.1 ✔ stringr 1.3.1
#> ✔ readr 1.1.1 ✔ forcats 0.3.0
#> ── Conflicts ─────────────────────── tidyverse_conflicts() ──
#> ✖ dplyr::filter() masks stats::filter()
#> ✖ dplyr::lag() masks stats::lag()
library(rap)
tbl <- tibble(cyl_threshold = c(4, 6, 8), mpg_threshold = c(30, 25, 20))
tbl
#> # A tibble: 3 x 2
#> cyl_threshold mpg_threshold
#> <dbl> <dbl>
#> 1 4 30
#> 2 6 25
#> 3 8 20
tbl %>%
rap(x = ~filter(mtcars, cyl == cyl_threshold, mpg < mpg_threshold))
#> # A tibble: 3 x 3
#> cyl_threshold mpg_threshold x
#> <dbl> <dbl> <list>
#> 1 4 30 <data.frame [7 × 11]>
#> 2 6 25 <data.frame [7 × 11]>
#> 3 8 20 <data.frame [14 × 11]>
If the lhs of the formula is empty, rap()
adds a list column. Otherwise the lhs can be used to specify the type:
tbl %>%
rap(
x = ~ filter(mtcars, cyl == cyl_threshold, mpg < mpg_threshold),
n = integer() ~ nrow(x)
)
#> # A tibble: 3 x 4
#> cyl_threshold mpg_threshold x n
#> <dbl> <dbl> <list> <int>
#> 1 4 30 <data.frame [7 × 11]> 7
#> 2 6 25 <data.frame [7 × 11]> 7
#> 3 8 20 <data.frame [14 × 11]> 14
this example is based on this issue, which has equivalent with pmap
:
tbl %>%
mutate(
x = pmap(
.l = list(cyl_threshold, mpg_threshold),
function(cc, mm) filter(mtcars, cyl == cc, mpg < mm)
),
n = map_int(x, nrow)
)
#> # A tibble: 3 x 4
#> cyl_threshold mpg_threshold x n
#> <dbl> <dbl> <list> <int>
#> 1 4 30 <data.frame [7 × 11]> 7
#> 2 6 25 <data.frame [7 × 11]> 7
#> 3 8 20 <data.frame [14 × 11]> 14
library(dplyr)
starwars <- head(starwars)
# creates a list of length 1 integer vectors
# because type not specified
starwars %>%
wap(~length(films))
#> [[1]]
#> [1] 5
#>
#> [[2]]
#> [1] 6
#>
#> [[3]]
#> [1] 7
#>
#> [[4]]
#> [1] 4
#>
#> [[5]]
#> [1] 5
#>
#> [[6]]
#> [1] 3
# using the lhs to specify the type
starwars %>%
wap(integer() ~ length(films))
#> [1] 5 6 7 4 5 3
# list of data frames
starwars %>%
wap(~ data.frame(vehicles = length(vehicles), starships = length(starships)))
#> [[1]]
#> vehicles starships
#> 1 2 2
#>
#> [[2]]
#> vehicles starships
#> 1 0 0
#>
#> [[3]]
#> vehicles starships
#> 1 0 0
#>
#> [[4]]
#> vehicles starships
#> 1 0 1
#>
#> [[5]]
#> vehicles starships
#> 1 1 0
#>
#> [[6]]
#> vehicles starships
#> 1 0 0
# Specify type as data.frame() row binds them
starwars %>%
wap(data.frame() ~ data.frame(vehicles = length(vehicles), starships = length(starships)))
#> vehicles starships
#> 1 2 2
#> 2 0 0
#> 3 0 0
#> 4 0 1
#> 5 1 0
#> 6 0 0
🍋 zest_join()
is similar to dplyr::nest_join()
but you control what goes in the nested column. Z
is N
but ⤵️.
tbl <- tibble(cyl_threshold = c(4, 6, 8), mpg_threshold = c(30, 25, 20))
tbl %>%
zest_join(mtcars, data = ~cyl == !!cyl_threshold & mpg < !!mpg_threshold)
#> # A tibble: 3 x 3
#> cyl_threshold mpg_threshold data
#> <dbl> <dbl> <list>
#> 1 4 30 <data.frame [7 × 11]>
#> 2 6 25 <data.frame [7 × 11]>
#> 3 8 20 <data.frame [14 × 11]>
In the rhs of the formula :
cyl
and mpg
refer to columns of mtcars
cyl_threshold
and mpg_threshold
refer to the current value from tbl
because these columns don't exist in mtcars. If you wanted to refer to columns that are present both in mtcars and tbl you would have to unquote the columns in tbl with the unquoting operator, e.g. !!cylAdd the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.