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.
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.
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