dplyr::group_by_ with character string input of several variable names

Question

I\'m writing a function where the user is asked to define one or more grouping variables in the function call. The data is then grouped using dplyr and it works as expected

Answer 1

slice_rows() from the purrrlyr package (https://github.com/hadley/purrrlyr) groups a data.frame by taking a vector of column names (strings) or positions (integers):

y <- c("cyl", "gear")
mtcars_grp <- mtcars %>% purrrlyr::slice_rows(y)

class(mtcars_grp)
#> [1] "grouped_df" "tbl_df"     "tbl"        "data.frame"

group_vars(mtcars_grp)
#> [1] "cyl"  "gear"

Particularly useful now that group_by_() has been depreciated.