Group input by rows
rowwise is used for the results of
do when you
create list-variables. It is also useful to support arbitrary
complex operations that need to be applied to each row.
- Input data frame.
rowwise grouping only works with data frames. Its
main impact is to allow you to work with list-variables in
mutate without having to
[]. This makes
summarise() on a rowwise tbl
effectively equivalent to plyr's
df <- expand.grid(x = 1:3, y = 3:1) df %>% rowwise() %>% do(i = seq(.$x, .$y)) .Last.value %>% summarise(n = length(i))