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R Data Visualization Cookbook by Atmajitsinh Gohil

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Editing a matrix in R

R allows us to edit (add, delete, or replace) elements of a matrix using the square bracket notation, as depicted in the following lines of code:

mat = matrix(c(1:10),nrow = 2, ncol = 5)
mat
mat[2,3]

How to do it…

In order to extract any element of a matrix, we can specify the position of that element in R using square brackets. For example, mat[2,3] will extract the element under the second row and the third column. The first numeric value corresponds to the row and the second numeric value corresponds to a column [row, column].

Similarly, to replace an element, we can type the following lines in R:

mat[2,3] = 16

To select all the elements of the second row, we can use mat[2, ]. If we do not specify any numeric value for a column, ...

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