splice

splice is an experimental package that brings some capabilities of dplyr::summarise_(all,if,at) to dplyr::summarise() directly.

Installation

You can install from github:

# install.packages("remotes")
devtools::install_github("romainfrancois/splice")

Example

The motivating example was “how do I get the mean of all variables AND the number of observations”.

There are many ways to get just that information, but I wanted to use dplyr::summarise_all() which would get me the means, but not the number of observations.

summarise(!!!all_(...)) is the same as summarise_all(...) but having !!!all_() inside summarise() lets you add other things as well:

library(dplyr, warn.conflicts = FALSE)
library(splice)

iris %>% 
  group_by(Species) %>% 
  summarise(n = n(), !!!all_(mean))
#> # A tibble: 3 x 6
#>   Species        n Sepal.Length Sepal.Width Petal.Length Petal.Width
#>   <fct>      <int>        <dbl>       <dbl>        <dbl>       <dbl>
#> 1 setosa        50         5.01        3.43         1.46       0.246
#> 2 versicolor    50         5.94        2.77         4.26       1.33 
#> 3 virginica     50         6.59        2.97         5.55       2.03

Similarly, if_() and at_():

iris %>%
  summarise(n = n(), !!!if_(is.numeric, mean))
#>     n Sepal.Length Sepal.Width Petal.Length Petal.Width
#> 1 150     5.843333    3.057333        3.758    1.199333

iris %>%
  summarise(n = n(), !!!at_(vars(starts_with("Sepal")), mean))
#>     n Sepal.Length Sepal.Width
#> 1 150     5.843333    3.057333