r - generating a vector of difference between two vectors

Question

I have two csv files, and each of which consists of one column of data

For instance, vecA.csv is like

id
1
2

vecB.csv is like

id
3
2

I read the data set as follows:

vectorA<-read.table("vecA.csv",sep=",",header=T)
vectorB<-read.table("vecB.csv",sep=",",header=T)

I want to generate a vector consisting of elements belonging to B only.

Answer 1

You are looking for the function setdiff

setdiff(vectorB$id, vectorA$id)

If you did not want this reduced to unique values, you could create a not in function

(kudos to @joran here Match with negation)

'%nin%' <- Negate('%in%')

vectorB$id[vectorB$id %nin% vectorA$id]