Creating simple matrix

Extracting the above values of the main diagonal in a matrix

The matrix can be created using the matrix() method which is used to arrange the specified data elements into the specified number of rows and columns. The method has the following syntax :

Syntax : matrix (data, nrow = rows, ncol = cols)

Parameters :

data – The data to be arranged into the matrix.

rows – The number of rows in matrix.

cols – The number of columns in matrix.

R

# declaring the number of rows
nrow <- 4
 
# declaring the number of columns
ncol <- 4
 
# creating matrix
mat <- matrix(1:16, nrow = nrow, 
              ncol = ncol)
 
# printing the matrix 
print ("Matrix : ")
print(mat)

Output

[1] "Matrix : " 
      [,1] [,2] [,3] [,4] 
[1,]    1    5    9   13 
[2,]    2    6   10   14 
[3,]    3    7   11   15 
[4,]    4    8   12   16

Extract Values Above Main Diagonal of a Matrix in R

In this article, we are going to know how to extract the values above the main diagonal of a matrix in the R programming language.

The main diagonal of a matrix is a straight path that connects the entries (or elements) in a matrix whose row and column are the same. The number of elements in the main diagonal is equivalent to either the number of rows or columns in the matrix. In matrix A, for every row i, and every column j of the matrix, the diagonal elements of the matrix are given by the following :

A_{ij where i=j}

Example:
Input Matrix : [[3, 1, 9],
               [8, 2, 3],
               [7, 11, 4]]
Output : 1, 9, 3
Explanation : In the above matrix the main diagonal is [3, 2, 4] 
and we have to extract values above main diagonal elements.
so, the answer will be 1, 9, 3

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#R Language

Extracting the above values of the main diagonal in a matrix

Creating simple matrix

R

Extract Values Above Main Diagonal of a Matrix in R

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