Aggregate daily level data to weekly level in R

Question

I have a huge dataset similar to the following reproducible sample data.

   Interval    value
1  2012-06-10   552
2  2012-06-11  4850
3  2012-06-12  4642
4          


        

Answer 1

If you were to use week from lubridate, you would only get five weeks to pass to by. Assume dat is your data,

> library(lubridate)
> do.call(rbind, by(dat$value, week(dat$Interval), summary))
#    Min. 1st Qu. Median Mean 3rd Qu. Max.
# 24  552    4146   4188 3759    4529 4850
# 25  490    2498   4256 3396    4438 5156
# 26  564    2578   4206 3355    4346 4866
# 27  698     993   4868 3366    5122 5770
# 28  671    1086   3200 3200    5314 5726

This shows a summary for the 24th through 28th week of the year. Similarly, we can get the means with aggregate with

> aggregate(value~week(Interval), data = dat, mean)
#   week(Interval)    value
# 1             24 3758.667
# 2             25 3396.286
# 3             26 3355.000
# 4             27 3366.429
# 5             28 3199.500