r - R How to Write Double for Loops and Store Result in a Matrix

Question

I would like to store result of X[i,j].

X[i,j] = alpha[i] + beta [j]

I tried writing this double for loop but could not get it to store the result. Appreciate any help here. Thanks!

for (i in length(alpha)) { 
  for (j in length(beta)) {
    Xij <- alpha[i] + beta[j]
    matrix[i,j] <- Xij
  }
}

Edit: Is there a more efficient way to do this? The for loop run is taking a long time as the dataset is huge.

标签： rfor-loop

Answer 1

for (i in 1:length(alpha)) { 
  for (j in 1:length(beta)) {
    Xij <- alpha[i] + beta[j]
    matrix[i,j] <- Xij
  }
}