[R] How to eliminate for next loops in this script

[ilai]

?by  ?aggregate

On Tue, Mar 6, 2012 at 4:14 PM, Walter Anderson <wandrson01 at gmail.com> wrote:
> I needed to compute a complicated cross tabulation to show weighted means
> and standard deviations and the only method I could get that worked uses a
> series of nested for next loops.  I know that there must be a better way to
> do so, but could use some assistance pointing the way.
>
> Here is my working, but inefficient script:
>
> library(Hmisc)
> rm(list=ls())
> load('NHTS.Rdata')
> day.wt <- day[c("HOUSEID","WTTRDFIN", "TRIPPURP","TRVLCMIN")]
> hh.wt <- hh[c("HOUSEID","WTHHFIN","HHSIZE","HHVEHCNT","HOMETYPE")]
> hh.wt$HHBIN <- with(hh.wt,{ cut(HHSIZE,
> breaks=c(0,1,2,3,4,max(HHSIZE)),labels=c("1","2","3","4","5+"),ordered_result=TRUE)})
> hh.wt$VEHBIN <- with(hh.wt,{ cut(HHVEHCNT,
> breaks=c(-1,0,1,2,max(HHVEHCNT)),labels=c("0","1","2","3+"),ordered_result=TRUE)})
> hh.wt$DUTYPE <- factor(hh.wt$HOMETYPE, exclude=c("-7","-8","-9"))
> levels(hh.wt$DUTYPE) <- c("1","1","2","2","2","2","2")  # Convert home
> types to 1=SF and 2=MF
> trips <- merge(day.wt,hh.wt,by="HOUSEID")
> trips$PURPOSE <- factor(trips$TRIPPURP, exclude=c("-9"))
> trips <- trips[c("HOUSEID","HHBIN","VEHBIN","DUTYPE","PURPOSE","WTTRDFIN",
> "WTHHFIN")]
> sink('TripRates.csv')
> cat("HHBIN,VEHBIN,DUTYPE,TRIPPURP,COUNT,MEAN,STD.DEV\n")
> for (per in levels(trips$HHBIN))
>  for (veh in levels(trips$VEHBIN))
>    for (hom in levels(trips$DUTYPE))
>      for (pur in levels(trips$PURPOSE))
>      {
>        cat(per)
>        cat(",")
>        cat(veh)
>        cat(",")
>        cat(hom)
>        cat(",")
>        cat(pur)
>        cat(",")
>        tmp <- subset(trips,
>                      trips$HHBIN == per & trips$VEHBIN == veh &
>                        trips$DUTYPE == hom & trips$PURPOSE == pur,
>                      select=c("HOUSEID","WTTRDFIN", "WTHHFIN"))
>        cat(length(tmp$HOUSEID))
>        cat(",")
>        tmp$tr <- (tmp$WTTRDFIN/365)/tmp$WTHHFIN
>        w.m <- wtd.mean(tmp$tr,weights=tmp$WTHHFIN)
>        w.sd <- sqrt(wtd.var(tmp$tr, weights=tmp$WTHHFIN))
>        cat(w.m)
>        cat(",")
>        cat(w.sd)
>        cat("\n")
>      }
> sink()
>
>        [[alternative HTML version deleted]]
>
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