multiple-rows-with-the-same-id-sum.R

library(dplyr)

## 
## Attaching package: 'dplyr'

## The following objects are masked from 'package:stats':
## 
##     filter, lag

## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union

# Example data frame with multiple rows per id
df <- data.frame(
  id = c(1, 1, 2, 2, 3),
  values = c(10, 20, 30, 40, 50)
)
df

##   id values
## 1  1     10
## 2  1     20
## 3  2     30
## 4  2     40
## 5  3     50

# Calculate the sum of values for each id
sum_by_id <- df %>%
  group_by(id) %>%
  summarise(sum_of_values = sum(values))
sum_by_id 

## # A tibble: 3 × 2
##      id sum_of_values
##   <dbl>         <dbl>
## 1     1            30
## 2     2            70
## 3     3            50