Get element at the specific position from matrix in R
At any point in time, a matrix may be required to be traversed for an element at a specific position. In this article, we are going to access the elements from a matrix in R Programming Language using integer vector, and logical vector as the index.
Accessing Elements in a Matrix
In R Programming Language we have several methods to Accessing Elements in a Matrix In R we can access matrix elements using square brackets [ ]
notation.
Create a matrix
R
# Create a matrix mat <- matrix (1:12,3,4) mat |
Output:
[,1] [,2] [,3] [,4]
[1,] 1 4 7 10
[2,] 2 5 8 11
[3,] 3 6 9 12
Accessing Single Element in a Matrix
R
# Create a matrix mat <- matrix (1:12,3,4) mat # Access the element in the 1st row and 2nd column element <- mat[1, 2] print (element) |
Output:
[,1] [,2] [,3] [,4]
[1,] 1 4 7 10
[2,] 2 5 8 11
[3,] 3 6 9 12
[1] 4
Accessing Entire Row or Column
R
# Access the entire 2nd row row_vector <- mat[2, ] print (row_vector) # Access the entire 3rd column col_vector <- mat[, 3] print (col_vector) |
Output:
[1] 2 5 8 11
[1] 7 8 9
Accessing Subsetting Matrix
R
# Create a 3x4 matrix mat <- matrix (1:12,3,4) # Subset a 2x2 matrix from the original subset_mat <- mat[1:2, 2:3] print (subset_mat) |
Output:
[,1] [,2]
[1,] 4 7
[2,] 5 8
Accessing matrix Conditional Access
R
# Create a 3x4 matrix mat <- matrix (1:12,3,4) # Access elements greater than 5 greater_than_5 <- mat[mat > 5] print (greater_than_5) |
Output:
[1] 6 7 8 9 10 11 12
These methods provide flexibility depending on our specific needs and the structure of our matrices. Choose the one that best fits our use case.