remove the first row for each group

Question

suppose I have a dataset like this

df <- data.frame(group = c(rep(1,3),rep(2,2), rep(3,2),rep(4,3),rep(5, 2)), score = c(30, 10, 22, 44, 6, 5, 20, 35, 2,         


        

Answer 1

dplyr::filter(df, group == lag(group))
   group score
1     1    10
2     1    22
3     2     6
4     3    20
5     4     2
6     4    60
7     5     5

See lead and lag of package dplyr for more information:

https://dplyr.tidyverse.org/reference/lead-lag.html