how to find indices of particular array elements
# create a 4x4 matrix with random values smallmatrix = matrix(runif(16)*10, ncol = 4, nrow = 4) # get the row and column number of the item in the matrix with the highest value which(smallmatrix == max(smallmatrix), arr.ind = 1) HTH, Martin --- Jonathan Williams
<jonathan.williams at pharmacology.oxford.ac.uk> wrote:
Dear R helpers, I have a largish matrix (1300 x 1300) and I wish to find the row and column numbers that identify particular elements whose values I know in advance (for example, the row and column numbers for the maximum value of the matrix). I have looked in the help manual and found the functions 'row' and 'col' for finding the indices of a matrix. But, I can't figure out how to use them to obtain the indices of the matrix element with maximum value, despite over an hour of trying! Many thanks for your help, Jonathan Williams
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