On 4/30/06, Guojun Zhu <[EMAIL PROTECTED]> wrote: > Hi. I am starting to learn R for a course project. I > am relative OK c++ programer. I found the R is very > different. I have read the "an introduction to R". I > have to say it is not very newbie friendly. It does > not explain many things clearly. And unfortunately, > there is not too much introductory materials available > on-line. I do not want to buy a book.
Enter R into google and you get the R home page. On the left pane of that under Documentation click on Other and from there click on Contributed Documentation and there is a list of literally dozens of different introductions. Also google for zoonekynd R for another online intro to R. > > For example, I found factor is a quite different > concept.I cannot use it as a vector which I can > somehow think as a 1-dimension array. help(factor) > does not help much to clear about the concept either. > Also there are quite few basic concepts like the data > structure of model, etc is far from clear for me. Yet > there is no general place I can look for there more > general idea. > > help is a very interesting and useful function. > However, I would say the content lacks some general > idea. I used to learn Mathematica, which is also a > high-level tool by their help. It is very > comprehensive, yet well-organized with some general > idea, some specific fundtion explanation and some > functions about one topic. For R's help, you get only > the specific explanation for the perticular function, > and no more related things. I feel it is more like a > reference for experienced user instead of some newbie. > > > > I know there should be some trick by R with some dense > code for big work. But unfortunately, I could not > find many place to learn it. > > > Now for a specific question, > > I use read.csv to read some data from an excel data > file (about 30,000 line data). Some columns has empty > data, so NA was read. But they were read in as a > factor instead of vector. I need to manipulate them > later as a vector (for example standardizing by > dividing with standard deviation, or derive a new > column from other two or more columns). How to > convert it into vector? Or maybe some functions > already exists for factor already? > Check out the na.strings= and possibly the as.is = TRUE arguments on read.table. Also the read.xls command from the gdata package may be helpful. ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
