r - dplyr summarise_each() using multiple functions for different column subsets accross the same groups -

i'd use summarise_each() apply multiple functions grouped dataset. however, rather apply each function all columns, i'd apply each function particular subsets. realize specifying each column summarise(), have many variables.

is there alternate solution either 1) using summarise_each() , deleting unneeded columns or 2) saving group_by() result, performing multiple separate summarise_each() operations , combining results?

if not clear, let me know , can try illustrate example code.

i suggest following: here apply min function 1 variable , max function other. merge grouping variable.

> by_species <- iris %>% group_by(species)     

start variable want apply min function:

min_var <- by_species %>% summarise_each(funs(min), petal.width) min_var source: local data frame [3 x 2]

      species petal.width        (fctr)       (dbl) 1     setosa         0.1 2 versicolor         1.0 3  virginica         1.4 

then variable want apply max function:

max_var <- by_species %>% summarise_each(funs(max), sepal.width) max_var source: local data frame [3 x 2]

     species sepal.width       (fctr)       (dbl)  1     setosa         4.4  2 versicolor         3.4  3  virginica         3.8 

now, merge above two:

left_join(min_var,max_var) joining by: "species" source: local data frame [3 x 3]

      species petal.width sepal.width      (fctr)       (dbl)       (dbl) 1     setosa         0.1         4.4 2 versicolor         1.0         3.4 3  virginica         1.4         3.8