[R] setting elements to NA across an array

[Dr Carbon]

Please excuse what is obviously a trivial matter...

I have a large 3-d array. I wish to set the third dimension (z) to NA
if there are any NA values in the first two dimnesions (xy). So, given
array foo:

  foo <- array(data = NA, dim = c(5,5,3))
  foo[,,1] <- matrix(rnorm(25), 5, 5)
  foo[,,2] <- matrix(rnorm(25), 5, 5)
  foo[,,3] <- matrix(rnorm(25), 5, 5)

I'll set two elements to NA

  foo[2,2,1]<- NA
  foo[3,5,2]<- NA
  foo

Now I want to set foo[2,2,] <- NA and foo[3,5,] <- NA. How can I build
a logical statement to do this?