dunner wrote on 09/28/2011 08:43:32 AM:
>
> Please help with this error message
>
> drugbook is an 885 x 32 dataframe
>
> >names(drugbook)
>
> [1] "DRUG1" "DRUG2" "DRUG3" "DRUG4" "DRUG5"
> [6] "DRUG6" "DRUG7" "DRUG8" "DRUG9" "DRUG10"
> [11] "DRUG11" "DRUG12" "DRUG13" "DRUG14" "DRUG15"
> [16] "DRUG16" "DrugDose1" "DrugDose2" "DrugDose3" "DrugDose4"
> [21] "DrugDose5" "DrugDose6" "DrugDose7" "DrugDose8" "DrugDose9"
> [26] "DrugDose10" "DrugDose11" "DrugDose12" "DrugDose13" "DrugDose14"
> [31] "DrugDose15" "DrugDose16"
>
> Equivs is a dataframe holding information for a certain subclass of
drugs
>
> > head(Equivs)
> Name Equiv
> 1 Alprazolam 0.5
> 2 Bromazepam 5.5
> 3 Chlordiazepoxide 25.0
> 4 Clobazam 20.0
> 5 Clonazepam 0.5
> 6 Clorazepate 15.0
>
> What I'm trying to is for each element of drugbook, get the value in
> Equivs$Equiv, and multiply it by the corresponding drug dose, which will
be
> in the n+16 th column on in the same row of drugbook.
>
> Not all of the grabbed names from Drugbook will be in the dataframe
Equivs,
> though. So sometimes the == will return a null.
>
> i.e. DrugDose16 is the dose of Drug 16
>
> this I think should work: ( I did try apply and got knotted, so stopped)
>
> >mydosequivalents=list()
> >for( c in 1:16) {
> for (r in 1:885){
> name<-as.character(drugbook[r,c]);
> equivalent<-Equivs$Equiv[Equivs$Name==name];
> dosequivalent<-drugbook[r,c+16] * equivalent;
> if (length(dosequivalent)>0) mydosequivalents[r][c]<-dosequivalent
> else (mydosequivalents[r][c]<-0)
> }
> }
>
> But it is throwing an error, and I can't figure out why. I remedied a
> previous error by checking the length of the equivalent.
I think your error is coming from the way that you are trying to populate
the list using [r][c]. Are you trying to have mydosequivalents be a list
of r vectors each with c elements?
> >warnings() ....
> 50: In mydosequivalents[c][r] <- dosequivalent :
> number of items to replace is not a multiple of replacement length
>
> mydosequivalents ends up being full of "NULL" and zeros
>
>
> Thanks in advance for any help
>
> Ross
Another way:
# using my example data
drugbook <- data.frame(DRUG1=letters[1:5], DRUG2=letters[6:10],
DrugDose1=1:5, DrugDose2=6:10)
Equivs <- data.frame(Name=letters[-c(2, 8)], Equiv=100*(1:24))
mydosequivalents <- apply(drugbook[, 1:2], 2,
function(x) Equivs$Equiv[match(x, Equivs$Name)])*drugbook[, 3:4]
mydosequivalents[is.na(mydosequivalents)] <- 0
# this should work for your real data
mydosequivalents <- apply(drugbook[, 1:16], 2,
function(x) Equivs$Equiv[match(x, Equivs$Name)])*drugbook[, 17:32]
mydosequivalents[is.na(mydosequivalents)] <- 0
Jean
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