Calculate the Sum of Matrix or Array columns in R Programming – colSums() Function

colSums() function in R Language is used to compute the sums of matrix or array columns.

Syntax: colSums (x, na.rm = FALSE, dims = 1)

Parameters:
x: matrix or array
dims: this is integer value whose dimensions are regarded as ‘columns’ to sum over. It is over dimensions 1:dims.

Example 1:

# R program to illustrate
# colSums function

# Initializing a matrix with 3
# rows and 3 columns
x <- matrix(rep(1:9), 3, 3)

# Getting the matrix representation
x

# Calling the colSums() function
colSums(x)

Output:

     [, 1] [, 2] [, 3]
[1, ]    1    4    7
[2, ]    2    5    8
[3, ]    3    6    9

[1]  6 15 24

Example 2:

# R program to illustrate
# colSums function

# Initializing a 3D array
x <- array(1:12, c(2, 3, 3))

# Getting the array representation
x

# Calling the colSums() function
colSums(x, dims = 1)
colSums(x, dims = 2)

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

     [, 1] [, 2] [, 3]
[1, ]    3   15    3
[2, ]    7   19    7
[3, ]   11   23   11

[1] 21 57 21

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