Convert numeric values into binary (0/1)

Question

I have a data frame with counts of different kinds of fruits of different people. Like below

    apple  banana  orange
Tim     3       0       2
Tom     0                


        

Answer 1

> pippo
  person apple banana orange
1    Tim     1      0      2
2    Tom     0      1      1
3    Bob     1      2      2
> cols <- c("apple", "banana", "orange")
> lapply(cols, function(x) {pippo[,x] <<- as.numeric(pippo[,x] >= 1)})