How to get Matrix Size in R - Step by Step Examples

How to get Matrix Size in R ?

Answer

To get the size of a matrix in R, you can use the dim() function. This function returns a vector containing the number of rows and columns of the matrix. Additionally, you can use the nrow() and ncol() functions to get the number of rows and columns separately.


✐ Examples

1 Getting the Dimensions of a Matrix

In this example,

  1. We create a matrix named matrix with values from 1 to 9 arranged in 3 rows and 3 columns using the matrix() function.
  2. The matrix() function takes a vector of values and the arguments nrow and ncol to specify the number of rows and columns respectively.
  3. We use the dim() function to get the dimensions of the matrix. The dim() function returns a vector where the first element is the number of rows and the second element is the number of columns.
  4. We store the dimensions in a variable named dimensions and print it to standard output.

R Program

matrix <- matrix(1:9, nrow = 3, ncol = 3)
dimensions <- dim(matrix)
print(dimensions)

Output

[1] 3 3

2 Getting the Number of Rows in a Matrix

In this example,

  1. We create a matrix named matrix with values from 1 to 12 arranged in 3 rows and 4 columns using the matrix() function.
  2. The matrix() function takes a vector of values and the arguments nrow and ncol to specify the number of rows and columns respectively.
  3. We use the nrow() function to get the number of rows in the matrix. The nrow() function returns a single integer value representing the number of rows.
  4. We store the number of rows in a variable named num_rows and print it to standard output.

R Program

matrix <- matrix(1:12, nrow = 3, ncol = 4)
num_rows <- nrow(matrix)
print(num_rows)

Output

[1] 3

3 Getting the Number of Columns in a Matrix

In this example,

  1. We create a matrix named matrix with values from 1 to 16 arranged in 4 rows and 4 columns using the matrix() function.
  2. The matrix() function takes a vector of values and the arguments nrow and ncol to specify the number of rows and columns respectively.
  3. We use the ncol() function to get the number of columns in the matrix. The ncol() function returns a single integer value representing the number of columns.
  4. We store the number of columns in a variable named num_columns and print it to standard output.

R Program

matrix <- matrix(1:16, nrow = 4, ncol = 4)
num_columns <- ncol(matrix)
print(num_columns)

Output

[1] 4

Summary

In this tutorial, we learned How to get Matrix Size in R language with well detailed examples.


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