> a <- c(2, 3, 7, 5) > b <- c(4, 7, 8, 9) > mapply(seq, from=a, to=b)
-Christos > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Rolf Turner > Sent: Tuesday, October 23, 2007 11:29 PM > To: Anya Okhmatovskaia > Cc: r-help@r-project.org > Subject: Re: [R] functions applied to two vectors > > > On 24/10/2007, at 4:15 PM, Anya Okhmatovskaia wrote: > > > Hi, > > > > I am very new to R, so I apologize if I have missed some > trivial thing > > in the manuals/archives. I am trying to get rid of for loops in my > > code and replace them with R vector magic (with no success). > > > > Let's say I have 2 vectors of the same length: > > a <- c(2, 3, 7, 5) > > b <- c(4, 7, 8, 9) > > > > What I'd like to do is to generate a list(?) of 4 sequences using a > > [i] as a start indices, and b[i] as end indices: > > 2,3,4 > > 3,4,5,6,7 > > 7,8 > > 5,6,7,8,9 > > > > My first guess: "a:b", of course, does not work - only one sequence > > gets generated using the first values from both vectors, plus a > > warning. > > Is there > > a special syntax I can use to make ":" treat its operands > as vectors? > > More generally, is there a standard way to apply some arbitrary > > functions to two or more vectors in an element-by-element > fashion? For > > instance, > > sum(a,b) > > will sum all values in both vectors; how can I make it produce a > > vector of pairwise sums instead? > > Cute question! The first idea that pops into my head is > > apply(cbind(a,b),1,function(x){x[1]:x[2]}) > > This works --- but there may be better ideas. > > cheers, > > Rolf Turner > > ###################################################################### > Attention:\ This e-mail message is privileged and > confid...{{dropped:9}} > > ______________________________________________ > 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. > > ______________________________________________ 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.
