[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. library(data.table) library(dplyr) data1 <- fread('/home/liuwensui/Downloads/2008.csv', header = T, sep = ',') dim(data1) # [1] 7009728 29 data2 <- data1 %.% filter(Year = 2008, Month %in% c(1, 2, 3, 4, 5, 6)) %.% select(Year, Month, AirTime) %.% group_by(Year, Month) %.% summarize(avg_time = mean(AirTime, na.rm = TRUE)) %.% arrange(desc(avg_time)) print(data2) # Year Month avg_time # 1 2008 3 106.1939 # 2 2008 2 105.3185 # 3 2008 6 104.7604 # 4 2008 1 104.6181 # 5 2008 5 104.3720 # 6 2008 4 104.2694 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 [...]

[Read more...]