More about Aggregation by Group in R

[This article was first published on Yet Another Blog in Statistical Computing » S+/R, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here)
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.

Motivated by my young friend, HongMing Song, I managed to find more handy ways to calculate aggregated statistics by group in R. They require loading additional packages, plyr, doBy, Hmisc, and gdata, and are extremely user-friendly. In terms of CPU time, while the method with summarize() is as efficient as the 2nd method with by() introduced yesterday, summaryBy() in doBy package seems the slowest.

“Learn as if you were to live forever” – Mahatma Gandhi

> # METHOD 5: USING DDPLY()
> library(plyr)
> summ5 <- ddply(df, .(SELFEMPL, OWNRENT), summarize, INCOME = mean(INCOME), BAD = mean(BAD))
> print(summ5)
  SELFEMPL OWNRENT   INCOME        BAD
1        0       0 2133.314 0.08470957
2        0       1 2881.201 0.06293210
3        1       0 2742.247 0.06896552
4        1       1 3487.910 0.05316973
> 
> # METHOD 6: USING DOBy()
> library(doBy)
> summ6 <- summaryBy(INCOME + BAD ~ SELFEMPL + OWNRENT, data = df, fun = c(mean), keep.names = TRUE)
> print(summ6)
  SELFEMPL OWNRENT   INCOME        BAD
1        0       0 2133.314 0.08470957
2        0       1 2881.201 0.06293210
3        1       0 2742.247 0.06896552
4        1       1 3487.910 0.05316973
>
> # METHOD 7: USING SUMMARIZE()
> library(Hmisc)
> summ7 <- summarize(df[c('INCOME', 'BAD', 'SELFEMPL', 'OWNRENT')], df[c('SELFEMPL', 'OWNRENT')], colMeans, stat.name = NULL)
> print(summ7)
  SELFEMPL OWNRENT   INCOME        BAD
1        0       0 2133.314 0.08470957
2        0       1 2881.201 0.06293210
3        1       0 2742.247 0.06896552
4        1       1 3487.910 0.05316973
> 
> # METHOD 8: USING FRAMEAPPLY()
> library(gdata)
> summ8 <- frameApply(df, by = c('SELFEMPL', 'OWNRENT'), on = c('INCOME', 'BAD'), fun = colMeans)
> rownames(summ8) <- NULL
> print(summ8)
  SELFEMPL OWNRENT   INCOME        BAD
1        0       0 2133.314 0.08470957
2        0       1 2881.201 0.06293210
3        1       0 2742.247 0.06896552
4        1       1 3487.910 0.05316973

Efficiency Comparison

> test5 <- function(n){
+   for (i in 1:n){
+     summ5 <- ddply(df, .(SELFEMPL, OWNRENT), summarize, INCOME = mean(INCOME), BAD = mean(BAD))
+   }
+ }
> system.time(test5(10))
   user  system elapsed 
  0.524   0.068   0.622 
>
> test6 <- function(n){
+   for (i in 1:n){
+     summ6 <- summaryBy(INCOME + BAD ~ SELFEMPL + OWNRENT, data = df, fun = c(mean), keep.names = TRUE)
+   }
+ }
> system.time(test6(10))
   user  system elapsed 
  1.800   0.060   1.903 
> 
> test7 <- function(n){
+   for (i in 1:n){
+     summ7 <- summarize(df[c('INCOME', 'BAD', 'SELFEMPL', 'OWNRENT')], df[c('SELFEMPL', 'OWNRENT')], colMeans, stat.name = NULL)
+   }
+ }
> system.time(test7(10))
   user  system elapsed 
  0.236   0.020   0.274 
> 
> test8 <- function(n){
+   for (i in 1:n){
+     summ8 <- frameApply(df, by = c('SELFEMPL', 'OWNRENT'), on = c('INCOME', 'BAD'), fun = colMeans)
+     rownames(summ8) <- NULL
+   }
+ }
> system.time(test8(10))
   user  system elapsed 
  0.580   0.008   0.668 

To leave a comment for the author, please follow the link and comment on their blog: Yet Another Blog in Statistical Computing » S+/R.

R-bloggers.com offers daily e-mail updates about R news and tutorials about learning R and many other topics. Click here if you're looking to post or find an R/data-science job.
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.

Never miss an update!
Subscribe to R-bloggers to receive
e-mails with the latest R posts.
(You will not see this message again.)

Click here to close (This popup will not appear again)