How would I inverse the binary digits (0 and 1) of a matrix in R?

Question

I have created a matrix of binary digits from reading in a pgm file using the R package pixmap but I am trying to inverse the binary digits (making all 0s become 1s and all 1s become 0s) and outputting the matrix again. Is there an efficient way of doing this?

Answer 1

matrix <- +(!matrix)

The ! coerces it into a logical matrix and switches the 0s and 1s to TRUE and FALSE. The + coerces it back to 0s and 1s.