Seeking help with a loop
You can do the following without resorting to a "hard coded" loop
sapply( paste("q35", letters[1:grep("r", letters)], sep=""), function(x)
ifelse(temp[, x]%in%1,temp[, sub("5", "3", x)],NA)
as the following example shows
temp <- matrix(sample(c(0,1), 360, replace=T), nrow=10)
colnames(temp) <- c(paste("q33", letters[1:grep("r", letters)], sep=""), paste("q35", letters[1:grep("r", letters)], sep=""))
sapply( paste("q35", letters[1:grep("r", letters)], sep=""), function(x) ifelse(temp[, x]%in%1,temp[, sub("5", "3", x)],NA))
HTH
Jean
On Wed, 3 Aug 2005, Greg Blevins wrote:
Hello R Helpers, After spending considerable time attempting to write a loop (and searching the help archives) I have decided to post my problem. In a dataframe I have columns labeled: q33a q33b q33c...q33r q35a q35b q35c...q35r What I want to do is create new variables based on the following logic: newfielda <- ifelse(q35a==1, q33a, NA) newfieldb <- ifelse(q35b==1, q33b, NA) ... newfieldr What I did was create two new dataframes, one containing q33a-r the other q35a-r and tried to loop over both, but I could not get any of the loop syntax I tried to give me the result I was seeking. Any help would be much appreciated. Greg Blevins Partner The Market Solutions Group, Inc. Minneapolis, MN Windows XP, R 2.1.1
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