How to use data.table In R Language
data.table package to calculate the sum of points scored by a team.
R
library(data.table) # convert data frame to data table setDT(df) # find sum of points scored by sub df[ ,list(sum=sum(Marks)), by=Sub] |
Output:
Sub sum Math 10 Phy 22 Che 8
How to Calculate the Sum by Group in R?
In this article, we are going to see how to calculate the Sum by Group in R Programming Language.
Data for Demonstration
R
# creating data frame 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)) # view dataframe df |
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
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