Reconstruct a categorical variable from dummies in R

Question

Heyho, I am a beginner in R and have a problem to which I couldn\'t find a solution so far. I would like to transform dummy variables back to categorical variables.

Answer 1

We can use max.col

data.frame(dummy = names(df1)[max.col(df1)])
#    dummy
#1 dummy2
#2 dummy1
#3 dummy2
#4 dummy3

data

df1 <- structure(list(dummy1 = c(0L, 1L, 0L, 0L), dummy2 = c(1L, 0L, 
 1L, 0L), dummy3 = c(0L, 0L, 0L, 1L)), .Names = c("dummy1", "dummy2", 
 "dummy3"), class = "data.frame", row.names = c(NA, -4L))