CODEWITHSUNDEEP
r
user1784579
user1784579

Reputation: 83

Assignment of value in R

How can I improve the speed of following codes?

for (i in 1:nrow(training)){
     score[training[i,1],training[i,2],training[i,4]] = training[i,3] 
  }

Training is a matrix with four columns. I just want to build an array which the value is training[i,3] according the formula above.

Thanks!

Upvotes: 0

Views: 58

Answers (1)

flodel
flodel

Reputation: 89097

You can index using a matrix. Here is the relevant part of ['s documentation:

A third form of indexing is via a numeric matrix with the one
 column for each dimension: each row of the index matrix then
 selects a single element of the array, and the result is a vector.

So in your case, the for loop can be replaced with:

score[training[, c(1, 2, 4)]] <- training[, 3]

Upvotes: 6

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