The rowSums() function calculates the sum of each row of a numeric array, matrix, or data frame. The colMeans() function calculates the mean of each column of a numeric array, matrix, or data frame. The rowMeans() function calculates the mean of each row of a numeric data frame, matrix, or array.
colSums in R
The colSums() is a built-in R function that calculates the sum of a column. The colSums() function takes an R object like an array of two or more dimensions and returns the sum of the columns.
The colSums() function calculates the sum of each column of a numeric data frame, matrix, or array. It forms the row and column sums and means for numeric arrays (or data frames).
Syntax
colSums(x, na.rm = FALSE, dims = 1)
Parameters
x: It is an array of two or more dimensions, containing numeric, complex, integer, or logical values, or a numeric data frame.
na.rm: It is logical. Should missing values (including NaN) be omitted from the calculations.
dims: It is an integer: Which dimensions are regarded as ‘rows’ or ‘columns’ to sum over.
Example
To create a matrix in R, use the matrix() function. We will use the rep() function to create a vector and then use the matrix() function to create a matrix function.
mtrx <- matrix(rep(1:4), 2, 2)
mtrx
Output
[,1] [,2]
[1,] 1 3
[2,] 2 4
Now, use the colSums() function to calculate the sum of column values of the matrix.
mtrx <- matrix(rep(1:4), 2, 2)
mtrx
cat("The sum of columns is: ", "\n")
colSums(mtrx)
Output
[,1] [,2]
[1,] 1 3
[2,] 2 4
The sum of columns is:
[1] 3 7
Finding the sum of column values of the 3D array.
To create a 3D array, use the array() function. Then, use the colSums() function to calculate the sum of columns of the array.
arr <- array(1:12, c(2, 3, 3))
arr
cat("The sum of columns is: ", "\n")
colSums(arr)
Output
, , 1
[,1] [,2] [,3]
[1,] 1 3 5
[2,] 2 4 6
, , 2
[,1] [,2] [,3]
[1,] 7 9 11
[2,] 8 10 12
, , 3
[,1] [,2] [,3]
[1,] 1 3 5
[2,] 2 4 6
The sum of columns is:
[,1] [,2] [,3]
[1,] 3 15 3
[2,] 7 19 7
[3,] 11 23 11
Calculating the sum of column values in R Data Set
You can use the inbuilt R dataset like ChickWeight and calculate the sum of its column values. But, first, let’s get the snapshot of the ChickWeight dataset using the head() function.
head(USArrests, 5)
Output
Murder Assault UrbanPop Rape
Alabama 13.2 236 58 21.2
Alaska 10.0 263 48 44.5
Arizona 8.1 294 80 31.0
Arkansas 8.8 190 50 19.5
California 9.0 276 91 40.6
We will use the colSums() function to calculate the sum of Murder, Assult, UrbanPop, and Rape column values.
colSums(USArrests)
Output
Murder Assault UrbanPop Rape
389.4 8538.0 3277.0 1061.6
That is it for colSums() function in R.
See also
Calculate the square of Number in R

Krunal Lathiya is a Software Engineer with over eight years of experience. He has developed a strong foundation in computer science principles and a passion for problem-solving. In addition, Krunal has excellent knowledge of Data Science and Machine Learning, and he is an expert in R Language.