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Using dplyr, you can sum across multiple columns by first grouping the data by the desired columns and then using the ‘summarise’ function to sum the grouped columns. This can be done with a single line of code and allows for the efficient summarisation of data across multiple columns.
You can use the following methods to sum values across multiple columns of a data frame using dplyr:
Method 1: Sum Across All Columns
df %>% mutate(sum = rowSums(., na.rm=TRUE))
Method 2: Sum Across All Numeric Columns
df %>% mutate(sum = rowSums(across(where(is.numeric)), na.rm=TRUE))
Method 3: Sum Across Specific Columns
df %>% mutate(sum = rowSums(across(c(col1, col2))))
The following examples show how to each method with the following data frame that contains information about points scored by various basketball players during different games:
#create data frame df <- data.frame(game1=c(22, 25, 29, 13, 22, 30), game2=c(12, 10, 6, 6, 8, 11), game3=c(NA, 15, 15, 18, 22, 13)) #view data frame df game1 game2 game3 1 22 12 NA 2 25 10 15 3 29 6 15 4 13 6 18 5 22 8 22 6 30 11 13
Example 1: Sum Across All Columns
The following code shows how to calculate the sum of values across all columns in the data frame:
library(dplyr)
#sum values across all columns
df %>%
mutate(total_points = rowSums(., na.rm=TRUE))
game1 game2 game3 total_points
1 22 12 NA 34
2 25 10 15 50
3 29 6 15 50
4 13 6 18 37
5 22 8 22 52
6 30 11 13 54
Example 2: Sum Across All Numeric Columns
The following code shows how to calculate the sum of values across all numeric columns in the data frame:
library(dplyr)
#sum values across all numeric columns
df %>%
mutate(total_points = rowSums(across(where(is.numeric)), na.rm=TRUE))
game1 game2 game3 total_points
1 22 12 NA 34
2 25 10 15 50
3 29 6 15 50
4 13 6 18 37
5 22 8 22 52
6 30 11 13 54 Example 3: Sum Across Specific Columns
The following code shows how to calculate the sum of values across the game1 and game2 columns only:
library(dplyr)
#sum values across game1 and game2 only
df %>%
mutate(first2_sum = rowSums(across(c(game1, game2))))
game1 game2 game3 first2_sum
1 22 12 NA 34
2 25 10 15 35
3 29 6 15 35
4 13 6 18 19
5 22 8 22 30
6 30 11 13 41
The following tutorials explain how to perform other common tasks using dplyr: