# What is the colSums() Function in R

The colSums() function in R is “used to calculate the sum of each column in a data frame or matrix”.

## Syntax

``colSums(x, na.rm = FALSE)``

## Parameters

1. x: It is an array of two or more dimensions containing numeric, complex, integer, or logical values or a numeric data frame.
2. na.rm: It is logical. Should missing values (including NaN) be omitted from the calculations?

## Example 1: Use colSums() with Data Frame

``````df <- data.frame(
run1 = c(11, 31, 23, 24, 52),
run2 = c(19, 21, 25, 32, 22),
run3 = c(21, 31, 62, 62, 82),
run4 = c(18, 11, 22, 14, 29)
)

colSums(df)``````

Output

`````` run1  run2  run3  run4
141  119   258    94
``````

## Example 2: Use the colSums() function with NA Values in Data Frame

You can exclude NA values from the data frame by passing the na.rm = TRUE parameter to the colSums() function.

``````df <- data.frame(
run1 = c(11, 31, NA, 24, 52),
run2 = c(19, 21, 25, NA, 22),
run3 = c(21, NA, 62, 62, 82),
run4 = c(NA, 11, 22, 14, 29)
)

colSums(df, na.rm = TRUE)
``````

Output

`````` run1  run2  run3  run4
118    87    227   76
``````

## Example 3: Use colSums() with specific columns

You can use the colSums() function to find the sum of the specific columns of a data frame.

``````df <- data.frame(
run1 = c(11, 31, 23, 24, 52),
run2 = c(19, 21, 25, 32, 22),
run3 = c(21, 31, 62, 62, 82),
run4 = c(18, 11, 22, 14, 29)
)

colSums(df[, c(2, 4)])``````

Output

`````` run2  run4
119   94
``````

## Example 4: Use the colSums() function on Matrix

You can 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``````

## Example 5: Calculating the sum of column values in 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’s it.

rowMeans() in R

rowSums() in R

colMeans() in R