On 08/11/2011 07:51 PM, William Dunlap wrote: >> -----Original Message----- >> From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On >> Behalf Of R. Michael >> Weylandt >> Sent: Thursday, August 11, 2011 10:09 AM >> To: Srinivas Iyyer >> Cc: r-help@r-project.org >> Subject: Re: [R] help with loops >> >> No problem, >> >> By the way, you can't (or at least shouldn't) use return() outside of a >> function -- that was the source of your old error message. >> >> If you, for whatever reason, couldn't use unlist() you would write: >> >> OurUnlist <- function(c, unique = F) { >> if (!is.list(c)) return(c) >> z <- NULL >> for (i in seq_along(c)) { >> z <- c(z,c[[i]]) >> } >> if (unique) return(unique(z)) >> return(z) >> } >> >> or some such. Still, I suggest you stick with built in functions whenever >> possible. > I tend to encourage people to write functions.
In addition, writing functions yourself is a good way to exercise your R skills. On the other hand, built in functions often solve the problem faster and are more generic. In my experience it takes quite a bit of R knowledge before one is good enough to beat a general, builtin function. Often a lengthy self written function can be replaced by one call to a built in function. In addition, it saves a lot of time when you use the already present functions. Several times I wanted something done in R, only to find out that it was already done. This meant getting the job done in 1 hour instead of two days of programming. In general I tend to agree with Michael and encourage people to stick with the builtin functions. my 2 cts ;), regards, Paul > I suppose you may end up reinventing the wheel, > but once you get used to writing functions it > is often faster to write a specialized one than > to find one that meets your needs. When you > discover a new idiom for your task (e.g., calling > unlist() instead of the for loop), you just edit > one function (OurUnlist) instead of editing all > your scripts that used the old idiom). > > Once you get used to writing functions (and using > them), you are ready to document them and package > them up for others to use. > > Bill Dunlap > Spotfire, TIBCO Software > wdunlap tibco.com > >> Michael Weylandt >> >> PS -- Can you email me (off list) and let me know what this is for? We've >> been asked this question a couple of times over the last few days and I'm >> just wondering why it's a calculation of interest to so many. >> >> On Thu, Aug 11, 2011 at 1:00 PM, Srinivas Iyyer >> <srini_iyyer_...@yahoo.com>wrote: >> >>> Thank you. that was very easy. >>> -srini >>> >>> --- On *Thu, 8/11/11, R. Michael Weylandt >>> <michael.weyla...@gmail.com>*wrote: >>> >>> >>> From: R. Michael Weylandt <michael.weyla...@gmail.com> >>> Subject: Re: [R] help with loops >>> To: "Srinivas Iyyer" <srini_iyyer_...@yahoo.com> >>> Cc: r-help@r-project.org >>> Date: Thursday, August 11, 2011, 12:49 PM >>> >>> >>> unlist() >>> >>> Michael Weylandt >>> >>> On Thu, Aug 11, 2011 at 12:46 PM, Srinivas Iyyer < >>> srini_iyyer_...@yahoo.com <http://mc/compose?to=srini_iyyer_...@yahoo.com> >>>> wrote: >>> hi I need help with list object. >>> >>> I have a list object >>> >>>> a <- c('apple','orange','grape') >>>> b <- c('car','truck','jeep') >>>> c <- list(a,b) >>>> names(c) <- c('fruit','vehicle') >>>> c >>> $fruit >>> [1] "apple" "orange" "grape" >>> >>> $vehicle >>> [1] "car" "truck" "jeep" >>> >>> >>> I want to write all the elements of this list in one object 'z'. >>> >>>> z >>> [1] "apple" "orange" "grape" "car" "truck" "jeep" >>> >>> How can I write the elements of c to z >>> I tried using a for loop. Could any one help me please. thanks >>> >>> >>>> z <- '' >>>> for (i in 1:length(c)){ >>> + k <- c[[i]] >>> + z <- c(z,k) >>> + return(z)} >>> Error: no function to return from, jumping to top level >>> >>> Thank you. >>> srini >>> >>> ______________________________________________ >>> R-help@r-project.org <http://mc/compose?to=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. >>> >>> >>> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> 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. -- Paul Hiemstra, Ph.D. Global Climate Division Royal Netherlands Meteorological Institute (KNMI) Wilhelminalaan 10 | 3732 GK | De Bilt | Kamer B 3.39 P.O. Box 201 | 3730 AE | De Bilt tel: +31 30 2206 494 http://intamap.geo.uu.nl/~paul http://nl.linkedin.com/pub/paul-hiemstra/20/30b/770 ______________________________________________ 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.
