Message-ID: <Pine.LNX.4.64.0904300745510.10625@tajo.ucsd.edu>
Date: 2009-04-30T14:55:24Z
From: Charles C. Berry
Subject: R Macro Question
In-Reply-To: <864852.36867.qm@web111508.mail.gq1.yahoo.com>
On Wed, 29 Apr 2009, Jenn wrote:
> Dear all,
>
> I?am?a?new?R?user,?and?I?have?a?question?about?R?macro.
>
> Here?is?the?situation,?I?want?to?do?item?option?analysis?(options?include:?A
> ,?B,?C,?D),?below?is?the?codes?for?option?A?analyses.
>
>
> #option?A?analyses
>
> optiona<-mat.or.vec(nrow(responsedata2),?ncol(responsedata2))
>
> #?create?A?matrix?by?recoding
> for?(i?in?1:ncol(responsedata2)){
> ??? optiona[,i]<-recode(responsedata2[,i],"'A'=1;NA=NA;else=0")
> }
>
> #?compute?mean?for?A?matrix
>
> pa<-rep(0,ncol(optiona))
> for?(i?in?1:ncol(optiona)){
> ??? pa[i]<-round(mean(optiona[,i],na.rm=TRUE),2)
> }
>
> pa1<-as.data.frame(pa)
> ?
> I?can?repeat?the?codes?for?other?options such as "B", "C" and "D",?but?I?am?wondering?if?I?can?do?it?
> in?a?macro?way--subsituting?"A"?"a"?in?the?codes?with?"B"?"b",?etc.
>
> In?SAS?it?can?be?done?easily,?but?I?could?not?get?it?to?work?in?R.
I suspect that 'it' can also be done easily in R.
But you have not really told the list what 'it' is.
You should provide some R code that actually works- as the R Posting Guide
recommends. The 'code' above is not syntactically valid R, so you haven't
really run it and neither can we.
The function 'recode' is not in base R, so you have to provide it or refer
to the contributed package frmo which it is obtained.
I can only guess what you are trying to do, but I'd say mapply() or one of
its relatives (lapply, tapply, ... ) is probably equal to the type of task
you wish to perform.
HTH,
Chuck
>
> Waiting?for?your?reply.
>
> And?thank?you?so?much?in?advance.
>
> Meng
>
>
>
> [[alternative HTML version deleted]]
>
>
Charles C. Berry (858) 534-2098
Dept of Family/Preventive Medicine
E mailto:cberry at tajo.ucsd.edu UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901