[R] Summing daily values by weekday and weekend

[Hu, Yinghua]

(Sorry for reposting. Please delete previous msgs. Thanks!)

Hi, all
 
Here I created a data frame like
 
mydates<- seq(as.Date("2010-05-29"), length = 43, by = "day")
myvalues<-runif(43,0,1)
myframe<-data.frame(dates=mydates, day=weekdays(dates), value=myvalues)
 
        dates       day      value
1  2010-05-29  Saturday 0.14576143
2  2010-05-30    Sunday 0.37669604
3  2010-05-31    Monday 0.74813943
4  2010-06-01   Tuesday 0.34677680
 
…
 
39 2010-07-06   Tuesday 0.69944349
40 2010-07-07 Wednesday 0.62712550
41 2010-07-08  Thursday 0.76714978
42 2010-07-09    Friday 0.72078298
43 2010-07-10  Saturday 0.80048954
 
How do I add weekday and weekend value in each week? I want a resulting data frame like
 
Dates                    day                         value
2010-05-29          weekend             0.5225
2010-05-31          weekday             2.2352
 
…
 
2010-07-05          weekday             3.xxxx
2010-07-10          weekend             0.8005
 
 
The closest I find is 
 
http://www.mail-archive.com/r-help@r-project.org/msg130580.html
 
But this one only summing values in each week, it does not sum values by weekday and weekend. I have been thinking of using functions such as aggregate, ddply, but without a clue. Anybody who can give some suggestions will be highly appreciated. Thanks!
 
Yinghua