Hello Jim, Thank you for getting back to me. Cumsum does exactly what I needed as the following example shows.
[1] TRUE FALSE FALSE FALSE TRUE FALSE FALSE FALSE FALSE TRUE FALSE FALSE FALSE FALSE TRUE FALSE > cumsum(x) [1] 1 1 1 1 2 2 2 2 2 3 3 3 3 3 4 4 4 4 4 5 5 5 5 5 6 6 6 6 6 7 7 7 7 Dan Stanger Eaton Vance Management 200 State Street Boston, MA 02109 617 598 8261 -----Original Message----- From: jim holtman [mailto:jholt...@gmail.com] Sent: Friday, June 18, 2010 12:24 PM To: Dan Stanger Cc: R-help@r-project.org Subject: Re: [R] Summing using a boolean index vector (repost in plain text). ?cumsum ?ave But without data (follow the posting guide) specific solution can not be specified On Fri, Jun 18, 2010 at 11:39 AM, Dan Stanger <dstan...@eatonvance.com> wrote: > Hello all: > I have a dataframe f of weekdays and value, and a Boolean vector with Fridays > set to true, and other days set to false, created by > fridays<-(diff(f$weekdays) < -1). > I would like to create a vector of sums, for each week. That is, start > summing on the first false value in the vector, and when I get to true, > produce the sum, and start summing again. > Is there a vector operation which can do this, without writing an explicit > loop? > Thank you, > Dan Stanger > P.S. Sorry about the repost. > Eaton Vance Management > 200 State Street > Boston, MA 02109 > 617 598 8261 > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve? ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
