Page 231 - Data Science class 11
P. 231
P <- matrix(c(3:14), nrow = 4, byrow = TRUE, dimnames = list(rownames, colnames))
print(P)
On execution of the above code, the following result is shown:
6.9.3 accessing elements of a matrix
Elements of a matrix can be accessed by using the column and row indexes of the element. We consider the matrix P
above to find the specific elements below.
The code snippet given below illustrates how you can access different elements in an array.
Example
Enter the following code snippet:
P <- matrix(c(3:14), nrow = 4, byrow = TRUE, dimnames = list(rownames, colnames))
print(P)
# Define the column and row names.
rownames = c("row1", "row2", "row3", "row4")
colnames = c("col1", "col2", "col3")
# Create the matrix.
P <- matrix(c(3:14), nrow = 4, byrow = TRUE, dimnames = list(rownames, colnames))
# Access the element at 3rd column and 1st row.
print(P[1,3])
# Access the element at 2nd column and 4th row.
print(P[4,2])
# Access only the 2nd row.
print(P[2,])
# Access only the 3rd column.
print(P[,3])
Programming with R 229

