Hi for the loop section runif needs curved brackets
Try IAP <-NA for (i in 1:Sample.Size){ if (DataSet$SES[i]>0) { IAP[i] <- ifelse(runif(1)>0.75, 1, 0) # High SES, higher chance to be in Treatment # } else { IAP[i] <- ifelse(runif(1)<=0.25, 1, 0) # Low SES, lower chance to be in Treatment # } } # End loop # IAP IAP zjiaqi19880219 wrote > Hi, all, > > I am working on a project to run a simulation. I am now working on the > main body of the simulation body, I generate the data and all work well > before I identify a variable "IAP", there is always an error message as > "replacement has length zero", and I do not know how to fix it. Can anyone > help? > > Here is the code: > > library (mvtnorm) > > options(digits=2) > > # Set variable name # > namelist1 <- c("Age", "Gender", "SES", "ISS", "IQTe", "PreTe") > > # Generate Data # > Sample.Size <- 10 # Variable Sample Size # > CorMat <- matrix(c(1.0 ,0.0 ,0.0 , 0.5, 0.2, 0.5, > 0.0, 1.0 ,0.0, 0.0, 0.0, 0.0, > 0.0 ,0.0 ,1.0, 0.5, 0.4, 0.5, > 0.5, 0.0, 0.5, 1.0, 0.4, 0.7, > 0.2, 0.0, 0.4, 0.4, 1.0, 0.9, > 0.5, 0.0, 0.5, 0.7, 0.9, 1.0),ncol=6) # > Correlation Matrix # > > DataSet <- rmvnorm(Sample.Size, mean=c(0,0,0,0,0,0), sigma=CorMat) # Draw > Sample.Size covariate set all mean 0 # > DataSet <- as.data.frame(DataSet) > names(DataSet) <- namelist1 > DataSet > > # For Treatment IAP # > IAP <- matrix(0, nrow=Sample.Size) > for (i in 1:Sample.Size){ > IAP[i] <- if (DataSet$SES>0) > { > ifelse(runif[1]>0.75, 1, 0) # High SES, higher chance to be in > Treatment > # > } > IAP[i] <- if (DataSet$SES<=0) > { > ifelse(runif[1]<=0.25, 1, 0) # Low SES, lower chance to be in > Treatment > # > } > } # End loop # > IAP > > Error in IAP[i] <- if (DataSet$SES > 0) { : replacement has length zero > In addition: Warning message: > In if (DataSet$SES > 0) { : > the condition has length > 1 and only the first element will be used > > Thanks! -- View this message in context: http://r.789695.n4.nabble.com/Why-replacement-has-length-zero-And-How-can-I-fix-it-tp4657373p4657380.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.