How to Calculate the Sum by Group in R?
Last Updated :
21 Feb, 2022
In this article, we are going to see how to calculate the Sum by Group in R Programming Language.
Data for Demonstration
R
df <- data.frame(Sub = c('Math', 'Math', 'Phy', 'Phy',
'Phy', 'Che', 'Che'),
Marks = c(8, 2, 4, 9, 9, 7, 1),
Add_on = c(3, 1, 9, 4, 7, 8, 2))
df
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Output:
Sub Marks Add_on
Math 8 3
Math 2 1
Phy 4 9
Phy 9 4
Phy 9 7
Che 7 8
Che 1 2
Method 1: Using aggregate() method in Base R
aggregate() function is used to get the summary statistics of the data by group. The statistics include mean, min, sum. max etc.
Syntax: aggregate(dataframe$aggregate_column, list(dataframe$group_column), FUN)
where
- dataframe is the input dataframe.
- aggregate_column is the column to be aggregated in the dataframe.
- group_column is the column to be grouped with FUN.
- FUN represents sum/mean/min/ max.
R
df <- data.frame(Sub = c('Math', 'Math', 'Phy', 'Phy',
'Phy', 'Che', 'Che'),
Marks = c(8, 2, 4, 9, 9, 7, 1),
Add_on = c(3, 1, 9, 4, 7, 8, 2))
aggregate(df$Marks, list(df$Sub), FUN=sum)
aggregate(df$Add_on, list(df$Sub), FUN=sum)
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Output:
Group.1 x
Che 8
Math 10
Phy 22
Group.1 x
Che 10
Math 4
Phy 20
Method 2: Using dplyr() package
group_by() function followed by summarise() function with an appropriate action to perform.
R
library(dplyr)
df %>%
group_by(Sub) %>%
summarise_at(vars(Marks),
list(name = sum))
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Output:
Sub name
Che 8
Math 10
Phy 22
Method 3: Using data.table
data.table package to calculate the sum of points scored by a team.
R
library(data.table)
setDT(df)
df[ ,list(sum=sum(Marks)), by=Sub]
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Output:
Sub sum
Math 10
Phy 22
Che 8
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