On Thu, 24 Feb 2022 11:00:08 -0500 Paul Bernal <paulberna...@gmail.com> wrote:
> Each pixel column in the training set has a name like pixel x, where > x is an integer between 0 and 783, inclusive. To locate this pixel on > the image, suppose that we have decomposed x as x = i ∗ 28 + j, where > i and j are integers between 0 and 27, inclusive. > I have been looking for information about how to process this with R, > but have not found anything yet. Given a 784-element vector x, you can reshape it into a 28 by 28 matrix: dim(x) <- c(28, 28) Or create a new matrix: matrix(x, 28, 28) Working with more dimensions is also possible. A matrix X with dim(X) == c(n, 784) can be transformed into a three-way array in place or copied into one: dim(X) <- c(dim(X)[1], 28, 28) array(X, c(dim(X)[1], 28, 28)) (Replace 28,28 with 784 for an inverse transformation. In modern versions of R, two-way arrays are more or less the same as matrices, but old versions may disagree with that in some corner cases.) For more information, see ?dim, ?matrix, ?array. -- Best regards, Ivan ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
