You can use the summarise_all function since summarise_each is deprecated.
For example:
library(dplyr)
by_species <- iris %>% group_by(Species)
by_species %>% summarise_all(list( minimum = ~ min(., na.rm = TRUE), maximum = ~ max(., na.rm = TRUE), s_dev = ~ sd(., na.rm = TRUE)))
# A tibble: 3 x 13
Species Sepal.Length_mi~ Sepal.Width_min~ Petal.Length_mi~ Petal.Width_min~ Sepal.Length_ma~
<fct> <dbl> <dbl> <dbl> <dbl> <dbl>
1 setosa 4.3 2.3 1 0.1 5.8
2 versic~ 4.9 2 3 1 7
3 virgin~ 4.9 2.2 4.5 1.4 7.9
# ... with 7 more variables: Sepal.Width_maximum <dbl>, Petal.Length_maximum <dbl>,
# Petal.Width_maximum <dbl>, Sepal.Length_s_dev <dbl>, Sepal.Width_s_dev <dbl>,
# Petal.Length_s_dev <dbl>, Petal.Width_s_dev <dbl>
If you want to explore more in R programming then watch this R programming tutorial for beginners: