CODEWITHSUNDEEP
ruser-defined-functionsreshape2
Reginald Roberts
Reginald Roberts

Reputation: 123

Passing data.frame variables names to melt and cast in r

I looked at several posts in order to get help to solve my issue, but no luck implementing a solution. My problem is simply, I want to pass a variable name to the cast function from the Reshape package. The variable "Time" is an argument in a user define function I am creating. I want to pass this argument through the cast function.

Pseudo Data I always use:

dates <-seq(as.Date("2010-01-01"), by = "day", length.out= 1080)
myData <- expand.grid( Day, Hour)
names(myData) <- c("Date","Hour")

myData$Adspend <- apply(myData, 1, function(x) foo(x[2], x[1]))
myData$Date <-dates

myData$Demand <-(rnorm(1,mean = 0, sd=1)+.75*myData$Adspend)

myData$Hour<-as.factor(myData$Hour)

Here is my partial user defined function I am testing:

AddLag <- function(DF,Date,Time,RESP,AD,LAG=9) {
    Lags<-24-LAG
    ADDATE<-DF[,c(1,2,4)]
    RESPDATE<-cbind(DF[[Date]],DF[[Time]],DF[[RESP]])
    HOURAD<-melt(ADDATE, id=c(Date,Time), measured =c(AD))
    HOURAD<- cast(HOURAD,as.formula(paste0(" ...~"),Time))

    return(HOURAD)
    }

The errors I am getting. I've tried various configurations of paste I suspect this is a simple problem that I can't figure out:

Bo<-AddLag(myData,"Date","Hour","Demand","Adspend")
Error in parse(text = x) : <text>:2:0: unexpected end of input
1:  ...~
   ^

Upvotes: 2

Views: 882

Answers (1)

Reginald Roberts
Reginald Roberts

Reputation: 123

I figured it out. It was a misunderstanding of how paste0 works with the as.formula function. Here is how the cast function should have been written:

require(reshape2)
HOURAD<- dcast(HOURAD,as.formula(paste0("... ~",Time))) ## was a parenthesis error here

Upvotes: 2

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