dummy coding problem
On 03/27/2014 05:34 AM, Si Qi L. wrote:
Hi, I have got a problem with dummy coding and I really couldn't figure it
out. Would you please help me out? this is my codes:
idx<-sort(unique(Employment.time$V1));
dummy<- matrix(NA, nrow=nrow(Employment.time), ncol= length(idx))
for (i in 1:nrow(Employment.time)) {
for (j in 1:length(idx)) {
if (Employment.time$V1[i,j] == "Over 4 years") {
dummy[i,j]<- 0
}
else {
dummy[i,j]<- 1
}
}
}
but the R shows that
Error in `[.default`(Employment.time$V1, i, j) :
incorrect number of dimensions
Do you know where is wrong? many thanks!
Hi Si Qi, It looks to me as though Employment.time$V1 is a column of a data frame and thus should be treated like a vector, not a matrix. If you want a dichotomous (two-valued) transformation of it, try this: dummy<-Employment.time$V1 != "Over 4 years" Jim