I would like to add a new variable to my data frame, which, for each group says the number of unique entries with relation to one variable (state), while disregaring others.
Data input
df <- data.frame(id=c(1,2,3,4,5,6,7,8,9),
state=c("CT","CT","AK","TX","TX","AZ","GA","TX","WA"),
group=c(1,1,2,3,3,3,4,4,4),
age=c(12,33,57,98,45,67,16,85,22)
)
df
Desired output
want <- data.frame(id=c(1,2,3,4,5,6,7,8,9),
state=c("CT","CT","AK","TX","TX","AZ","GA","TX","WA"),
group=c(1,1,2,3,3,3,4,4,4),
age=c(12,33,57,98,45,67,16,85,22),
count=c(1,1,1,2,2,2,3,3,3)
)
want
CodePudding user response:
We need a group by n_distinct
library(dplyr)
df %>%
group_by(group) %>%
mutate(count = n_distinct(state)) %>%
ungroup