[R] length of variable in mlogit

[R. Michael Weylandt]

On Fri, Aug 3, 2012 at 4:27 AM, Lee van Cleef <l.van.cleef at gmx.net> wrote:
> Ingmar,
>
> many thanks for your answer.
>
> I give you a smaller version of my program with the isolated "strange"
> variable, which I used when trying to elaborate the problem .
>
> [Start of R-Editor quote]
> library(foreign)
> library(gdata)
> library(gtools)
> library(gmodels)
> library(gplots)
> library(xtable)
> library(mlogit)
> library(survival)
>
> #First I import the data, a survey in the wide format.
> masterdata <- read.dta("E:/Masterdata.dta")

I'm afraid this line makes it hard for us to reproduce this otherwise
quite helpful example: can you give us dput(head(masterdata, 20))
which will give a plain text representation of the same? Don't worry
if you can't understand what shows up -- it's super helpful for us.

Best,
Michael

>
> #Then I define the number of cases which is the dimension of rows of the
> imported dataset.
>
> cases <- dim(masterdata)[1]
>
> # The conditional Logit-Model must have the form Y = aX, with Y as the
> choice variable
> # and X as the explaining one.
>
> # These are the headings for the explaining variable.
> Numbers <- c("2", "3", "4", "5", "6", "7")
>
> # I define the matrix for the explaining variable. ncol corresponds to the
> number of choices; cases is the number of people surveyed.
> X <- matrix(0, ncol=6, nrow=cases)
>
> # I define the choice variable. First, the answers become numeric values,
> the I define the n.a.'s.
> Y <- as.numeric(masterdata[,"V3D"])
> Y[Y == 1 | Y ==8 | Y == 9 | Y == 10 | Y == 11] <- NA
> Y <- as.factor(Y - 1)
>
> #I import the answers from the survey in my matrix for the explaining
> variable.
> for (i in 1:5){X[,i][as.numeric(factor(masterdata$VS))==i] <- 1}
> colnames (X) <- paste("X", Numbers, sep=".")
> # I put my data set together and delete the NA options.
> masterdata.wide <- cbind (Y, X)
> masterdata.wide <- na.omit(masterdata.wide)
> head(masterdata.wide)
>
> masterdata.long <- mlogit.data(masterdata.wide, varying = c(2:7), shape =
> "wide", choice = "Y")
>
> [End of R-Editor quote]
>
> The first problem arises before the Condlog-order. R does not transform wide
> into long and says: Error in data[[choice]] : subscript out of bounds
>
> In the extended version, transforming from wide to long is no problem, no
> idea why. But then, R says after Condlog: Error in
> model.frame.default(terms(formula, lhs = lhs, rhs = rhs, data = data),  :
> variable lengths differ (found for 'X').
>
> Other variables (alternative specific or with a generic regression
> coefficient) apart from X work. I checked the variable lengths, but the
> complete Logit-Model is working without problems for other variables with
> the same lengths.
>
> Which options do I have to address the problems with X? I did not find
> anything via the Str-Option on first sight.
>
> Any comment where and how I can look for would really be appreciated.
>
> Best regards!
>
>
>
>
>
>
>
>
> --
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