R help - Dec 2007 - counting weekday in a month in R

Hi,

I am trying to count weekday of the month using R. For example, 1/4/2001
is the 4th weekday of Jan, and 1/5/2001 is the 5th weekday of the month, and
1/8/2001 is the 6th weekday of the month, etc. I get as far as extracting
the weekdays from a sequence of dates (see below). But I have not yet
figured out a fast way of counting without using a For Loop. Does anyone
know how to do such counting efficiently in R?

Thanks!

library(chron)
dts=seq(dates("1/4/01"),dates("3/31/01"),1)
wkday=dts[!is.weekend(dts)]
weekdays(wkday)
 [1] Thu Fri Mon Tue Wed Thu Fri Mon Tue Wed Thu Fri Mon Tue Wed Thu Fri Mon
Tue Wed
[21] Thu Fri Mon Tue Wed Thu Fri Mon Tue Wed Thu Fri Mon Tue Wed Thu Fri Mon
Tue Wed
[41] Thu Fri Mon Tue Wed Thu Fri Mon Tue Wed Thu Fri Mon Tue Wed Thu Fri Mon
Tue Wed
[61] Thu Fri
Levels: Sun < Mon < Tue < Wed < Thu < Fri < Sat



-- 
Tom

	[[alternative HTML version deleted]]

> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of tom soyer
> Sent: Thursday, December 13, 2007 1:27 PM
> To: r-help at r-project.org
> Subject: [R] counting weekday in a month in R
> 
> Hi,
> 
> I am trying to count weekday of the month using R. For 
> example, 1/4/2001
> is the 4th weekday of Jan, and 1/5/2001 is the 5th weekday of 
> the month, and
> 1/8/2001 is the 6th weekday of the month, etc. I get as far 
> as extracting
> the weekdays from a sequence of dates (see below). But I have not yet
> figured out a fast way of counting without using a For Loop. 
> Does anyone
> know how to do such counting efficiently in R?
> 
> Thanks!
> 
> library(chron)
> dts=seq(dates("1/4/01"),dates("3/31/01"),1)
> wkday=dts[!is.weekend(dts)]
> weekdays(wkday)
>  [1] Thu Fri Mon Tue Wed Thu Fri Mon Tue Wed Thu Fri Mon Tue 
> Wed Thu Fri Mon
> Tue Wed
> [21] Thu Fri Mon Tue Wed Thu Fri Mon Tue Wed Thu Fri Mon Tue 
> Wed Thu Fri Mon
> Tue Wed
> [41] Thu Fri Mon Tue Wed Thu Fri Mon Tue Wed Thu Fri Mon Tue 
> Wed Thu Fri Mon
> Tue Wed
> [61] Thu Fri
> Levels: Sun < Mon < Tue < Wed < Thu < Fri < Sat
> 
> 
> 
> -- 
> Tom
How about length(wkday) ?

Hope this is helpful,

Dan

Daniel J. Nordlund
Research and Data Analysis
Washington State Department of Social and Health Services
Olympia, WA  98504-5204