sort and split a vector into n group

[veda]

Hi R experts,

I would like sort a vector by its values (1,2,2,3,3,3,3,4,4,5) and split them into three groups. There are ties in the vector so I need to deal with ties by average. Hence, it is not necessary to have equal group size. I guess that I could use rank(x,ties.method='average') and cut(x) but I am not sure how to put the functions together. Can any one help me out? Thanks.

Veda

[Col]

You were on track. The ties.method of 'average' still runs into duplication. However, using ties.method 'first' will sort and then split. I threw in numbers at the beginning of your vector to make sure this worked out.

library(tidyverse)

df <- tibble( x = c(5,3,1,2,2,3,3,3,3,4,4,5))
n_groups = 3

#included just to see the difference
rank(df$x, ties.method = 'average')
rank(df$x, ties.method = 'first')

df%>%
  mutate(grouping = cut(rank(x, ties.method = 'first', na.last = 'keep')
                      ,  breaks = n_group
                      , labels = FALSE))