Table of Contents
In R, you can create an empty matrix by using the matrix() function with nrow and ncol arguments set to 0. For example, the following code creates a 3×4 empty matrix: matrix(nrow=3, ncol=4). You can also create empty matrices of specific data types, such as integer or character, by using the additional argument “byrow” or “bycol” and specifying the type of data. In addition, you can also create an empty matrix by using the list() or cbind() functions. All of these methods can be used to quickly and easily create an empty matrix in R.
You can use the following syntax to create an empty matrix of a specific size in R:
#create empty matrix with 10 rows and 3 columns empty_matrix <- matrix(, nrow=10, ncol=3)
The following examples show how to use this syntax in practice.
Example 1: Create Empty Matrix of Specific Size
The following code shows how to create an empty matrix of a specific size in R:
#create empty matrix with 10 rows and 3 columns empty_matrix <- matrix(, nrow=10, ncol=3) #view empty matrix empty_matrix [,1] [,2] [,3] [1,] NA NA NA [2,] NA NA NA [3,] NA NA NA [4,] NA NA NA [5,] NA NA NA [6,] NA NA NA [7,] NA NA NA [8,] NA NA NA [9,] NA NA NA [10,] NA NA NA #view class class(empty_matrix) [1] "matrix" "array"
The result is a matrix with 10 rows and 3 columns in which every element in the matrix is blank.
Example 2: Create Matrix of Unknown Size
If you don’t know what the final size of the matrix will be ahead of time, you can use the following code to generate the data for the columns of the matrix and bind each column together using the function:
#create empty list my_list <- list() #add data using for loop for(i in 1:4) { my_list[[i]] <- rnorm(10) } #column bind values into a matrix my_matrix = do.call(cbind, my_list) #view final matrix my_matrix [,1] [,2] [,3] [,4] [1,] 1.3064332 1.18175760 2.1603867 1.2378847 [2,] 0.8618439 0.66663694 0.1113606 0.2062029 [3,] -0.4689356 -0.03200797 -1.3872632 1.6531437 [4,] -0.4664767 -0.79285400 0.3972758 0.1632975 [5,] 0.5880580 1.05795303 -0.5655543 -0.3557376 [6,] 0.5412100 -0.32070294 -0.3687303 -1.1778959 [7,] 0.5073627 -0.24925226 1.0031305 0.6336998 [8,] 0.8047177 0.10968558 0.3225197 1.6776955 [9,] 1.5755134 1.40435730 1.8360239 0.5612274 [10,] -0.6430913 0.01173386 0.3181037 -0.8414270
The result is a matrix with 10 rows and 4 columns.
The following examples show how to create other empty objects in R: