R count over group in a dataframe

Question

I have a dataframe that looks like the following:

df<-data.frame(group=c("A","A","B"))

What's the simplest way of adding another column to this that has the count of each occurrence of the column group?

The result should look like the following:

  group count
1     A     2
2     A     2
3     B     1

https://stackoverflow.com/questions/7450600/count-number-of-rows-per-group-and-add-result-to-original-data-frame — user63230, Jul 27 '22 at 11:26

score -1 · Answer 1 · answered Jul 27 '22 at 11:22

-1

library(dplyr)

df %>% 
  group_by(group) %>% 
  mutate(count = n())

answered Jul 27 '22 at 11:22

Julian

1 Answers1