Summing over particular columns of data frame in R

Question

I would like to do use some of Excel's pivot table functionalities in data frames of R. I can do what I want with some length coding, but I am wondering if there is an easy way to do it.

Assume I have the following data frame:

name<-c("Mexico","France","Chile","Germany","Sudan") 
continent<-c("Am","Eur","Am","Eur","Afr") 
population<-c(1000,2000,3500,2500,2000) 
countries<-data.frame(name,continent,population)

I want to get a new data frame only with columns continents and population, where the population is summed over countries. So I want this get this one:

> continents
continent population
1 Am 4500
2 Eur 4500
3 Afr 2000

Any easy way for it?

`library(dplyr);countries %>% group_by(continent) %>% summarise(population=sum(population))` — Khashaa, Jan 16 '15 at 20:42

score 4 · Accepted Answer · edited May 23 '17 at 12:24

4

you could use aggregate

> aggregate(population~continents, data=countries, FUN=sum)
  continents population
1        Afr       2000
2         Am       4500
3        Eur       4500

Take a look at this answer for further alternatives

edited May 23 '17 at 12:24

Community

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answered Jan 16 '15 at 20:42

Jilber Urbina

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Thanks! Exactly what I wanted. – Baykal Jan 16 '15 at 20:44

Summing over particular columns of data frame in R

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