You need to have a look at Chapter 5 of the Intro to R. I would recommend downloading the pdf and printing it out. It is not an easy read but it should help.
newdata <- mydata[, c(PUMDID, Y_Q10A)] or newdata <- mydata[, c(1,33)] should do the trick --- Natalie O'Toole <[EMAIL PROTECTED]> wrote: > Hi, > > Does anyone know how to skip variables (or columns) > in R. Say, for example > i had PUMFID position1 and Y_Q10A position 33 and i > do not want to include > all the variables in between. Is there a way to do > this in R when you are > extracting variables from a large .txt file with > many, many variables? > > Thanks, > > Nat > > __________________ > > > Yes but I believe it will vary depending on what > package you're using. I don't deal with weigthed > data > so I'm not a good source > > Have a look at help for something like lm in the > stats > package (part of the base installation) for an > example. > > ?lm > > weight is the fourth argument down. > > However for more information try > http://finzi.psych.upenn.edu/search.html and type in > weight. > > As Brian Ripley says in a reply to a question about > weights: > "Almost all methods I know of do: logistic > regression, neural nets, classification trees, PPR > .... " > > > --- Natalie O'Toole <[EMAIL PROTECTED]> wrote: > > > Hi, > > > > Thank-you for the response!! That worked great!! > Is > > there any way to apply > > a weight variable to your file similar to what you > > can do in SPSS? So that > > all of your other variables will be weighted by > the > > weight variable? > > > > Thanks, > > > > Nat > > > > __________________ > > > > > > Hi, > > > > i am trying to read a .txt file, do a couple of > > select if statements on my > > data, and then finally use the ?table function to > > get frequency counts on > > the data. Specifically, i am looking at answering > > the following question: > > > > What is the frequency of Grade 7 students in the > > province of Alberta who > > are smokers? > > > > I am having some problems: > > > > 1)i cannot get the column names to show up when > > print to screen > > > > 2)I cannot seem to skip variables properly when i > > choose certain other > > variables > > > > 3)i cannot get the combination of Select If > > statements to work to produce > > a different table with my new criteria > > > > Here are the variables > > > > PUMFID position1 length 5 > > PROV position 6 length 2 > > GRADE position 9 length 2 > > Y_Q10A position 33 length 1 > > > > > > Y_Q10A has the following 1=yes > > 2=no > > 9=skip > > > > all the others have no skipped or missing values > > > > Here is my code: > > > > myfile<-("c:/test2.txt") > > > myVariableNames<-c("PUMFID","PROV","GRADE","Y_Q10A") > > > > myVariableWidths<-c(5,2,2,1) > > > > > > mydata<-read.fwf( > > file=myfile, > > width=myVariableWidths, > > col.names=myVariableNames, > > row.names="PUMFID", > > fill=TRUE, > > strip.white=TRUE) > > > > > > print(mydata) > > > > print( mydata [which(PROV=="AB" & GRADE==7 & > > Y_Q10A<9), ] ) > > > > > > > > Any help would be greatly appreciated!! > > > > Thank-you, > > > > Nat > > > > > ------------------------------------------------------------------------------------------------------------------------ > > > > > > This communication is intended for the use of the > > recipient to which it is > > addressed, and may > > contain confidential, personal, and or privileged > > information. 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