Break for loop in R

Question

I have

sx <- structure(c(17, 11, 4, 0, 17, 11, 9, 15, 26, 12, 9, 0, 11, 9, 12, 5, 0, 9), .Dim = c(3L, 6L))

I need to break the value = 0. I used that function:

for (i in 1:ncol(sx)) {
  for (j in 1:nrow(sx)) {
    if (sx[j,i] == 0) {
      break
    }
    else 
    {
      sx[j,i] <- sx[j,i]
    }
  }
}

but it doesn't work. My expected output is

sx <- structure(c(17, 11, 4, 9, 17, 11, 12, 15, 26, 11, 9, 12, 9, 5, 9), .Dim = c(3L, 5L))

How can I do? Thx