gakera gakera - 9 months ago 33
R Question

Count unique values in R

Let's say I have

v = rep(c(1,2, 2, 2), 25)


Now, I want to count the number of times each unique value appears.
unique(v)
 returns what the unique values are, but not how many they are.

> unique(v)
[1] 1 2


I want something that gives me

length(v[v==1])
[1] 25
length(v[v==2])
[1] 75


but as a more general one-liner :) Something close (but not quite) like this:

#<doesn't work right> length(v[v==unique(v)])

Answer Source

Perhaps table is what you are after?

dummyData = rep(c(1,2, 2, 2), 25)

table(dummyData)
# dummyData
#  1  2 
# 25 75

## or another presentation of the same data
as.data.frame(table(dummyData))
#    dummyData Freq
#  1         1   25
#  2         2   75