How to extract an element of a matrix by indexing based on column or row names? Explain
For extracting an element of a matrix,let us define a matrix along with row and column names
Matrix <- matrix(1:15, nrow=3)
rownames(Matrix) <- c("X", "Y","Z")
colnames(Matrix) <- c("A", "B", "C", "D", "E")
Matrix
A B C D E
X 1 4 7 10 13
Y 2 5 8 11 14
Z 3 6 9 12 15
Now to extract an element of a matrix, we can do the following
Matrix["X", "A"]
[1] 1
Matrix["X", ]
Output
A B C D E
1 4 7 10 13