How to aggregate data in R with mode (most common) value for each row?

Question

I have a data set for example,

Data <- data.frame(
  groupname = as.factor(sample(c(\"a\", \"b\", \"c\"), 10, replace = TRUE)),
  someuser = sample(c(\"x\         


        

Answer 1

You can combine this function for finding the mode with aggregate.

Mode <- function(x) {
  ux <- unique(x)
  ux[which.max(tabulate(match(x, ux)))]
}

aggregate(someuser ~ groupname, Data, Mode)

  groupname someuser
1         a        x
2         b        x
3         c        x

Note that in the event of a tie, it will only return the first value.