Question

I have data collected from a survey. One factor variable is like this:

Column1  Column2  Column3  Column4  Column5
A        B        C
B        C
A        B        C        D        E
A        C        E
C        E
B        D        E

In other words, classes are spread in many different variables. I want to create one binary variable (1 or 0) for each class (A, B, C, D, E). However it’s not clear to me how to do it. How can I do it?

EDIT

The output would be something like this:

A      B      C      D      E
1      1      1      0      0
0      1      1      0      0
1      1      1      1      1
1      0      1      0      1
0      0      1      0      1
0      1      0      1      1

Answer 1

> data <- data.frame(Column1=c("A","B","A"),Column2=c("B","A","A"))
> data
  Column1 Column2
1       A       B
2       B       A
3       A       A
> f <- unique(unlist(data))
> tb <- data.frame(sapply(f, function(x) (rowSums(data == as.character(x)) != 0)*1))
> names(tb) <- f
> tb
  A B
1 1 1
2 1 1
3 1 0