R: Converting multiple binary columns into one factor variable whose factors are binary column names

Question

I am a new R user. Currently I am working on a dataset wherein I have to transform the multiple binary columns into single factor column

Here is the example:

Answer 1

> mat <- matrix(c(0,1,0,0,0,
+                 1,0,0,0,0,
+                 0,0,0,1,0,
+                 0,0,1,0,0,
+                 0,0,0,0,1), ncol = 5, byrow = TRUE)
> colnames(mat) <- c("Level1","Level2","Level3","Level4","Level5")
> mat
     Level1 Level2 Level3 Level4 Level5
[1,]      0      1      0      0      0
[2,]      1      0      0      0      0
[3,]      0      0      0      1      0
[4,]      0      0      1      0      0
[5,]      0      0      0      0      1

Create a new factor based upon the index of each 1 in each row Use the matrix column names as the labels for each level

NewFactor <- factor(apply(mat, 1, function(x) which(x == 1)), 
                    labels = colnames(mat)) 

> NewFactor 
[1] Level2 Level1 Level4 Level3 Level5 
Levels: Level1 Level2 Level3 Level4 Level5 

also you can try:

factor(mat%*%(1:ncol(mat)), labels = colnames(mat)) 

also use Tomas solution - ifounf somewhere in SO

as.factor(colnames(mat)[mat %*% 1:ncol(mat)])