Is there a way or a built in R function that can sum the values of duplicate names within a list?

user_11017815 0
Viewed 56

lets say I have this list:

values <- list(2, 8, 3, 21, 54, 2, 43, 31)
countries <- list('US', 'UK', 'China', 'US', 'Russia', 'UK', 'US', 'China')
names(values) <- countries

Then, values looks like:('US' = 2, 'UK' = 8, 'China' = 3, 'US' = 21, 'Russia' = 54, 'UK' = 2, 'US' = 43, 'China' = 31)

Is there a built-in function in R or some short way to add the values of the duplicates? Meaning, to make values become: ('UK' = 10, 'China' = 34, 'Russia' = 54, 'US' = 66) (The order doesn't matter though)

names duplicates r list
3 Answers

An option using tidyverse

library(dplyr)
library(tibble)
library(tidyr)
enframe(values) %>%
    unnest(c(value)) %>% 
    group_by(name) %>% 
    summarise(value = sum(value)) %>%
    deframe %>% 
    as.list
#$China
#[1] 34

#$Russia
#[1] 54

#$UK
#[1] 10

#$US
#[1] 66

Or using base R

as.list(tapply(unlist(values), names(values), sum))
#$China
#[1] 34

#$Russia
#[1] 54

#$UK
#[1] 10

#$US
#[1] 66
user_37322710

One option could be:

as.list(with(aggregate(values ~ ind, sum, data = stack(values)), 
             setNames(values, ind)))

$US
[1] 66

$UK
[1] 10

$China
[1] 34

$Russia
[1] 54
user_59645570 
sapply(unique(countries), function(x){sum(unlist(values[names(values)==x]))})

also works. At first i did not see that you had lists.

user_84252700
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