search for: chemsitri

Hi, there. I have two matrix with identical dimentions. matrix A contains information of 0 and 1, and matrix B contains data. I only want the data in matrix B where matrix A has 1's. the places where matrix A has 0's, I want NA's in matrix B. How do I do that?? Thank you very much. Lei Jiang Department of Chemsitry University of Washington Box 351700 Seattle, WA 98195 Phone:

I have a data frame. And I'd like to subset according to rownames. subset(mydataframe, rownames(mydataframe) == myrow, select = mycols) it turned out that "myrow" cannot be a vector. But I have multiple rows to pick. Is there a way to get around this problem?? Thank you for your help!! Lei Jiang Department of Chemsitry University of Washington Box 351700 Seattle, WA 98195

Hi, there. I am trying to read multiple files into R, but I got following message Error in file(file, "r"): All connections are in use. I clean up memory everytime I read in one file. Do i have to somehow release file connection everytime i read in one?? Thanks. Lei Department of Chemsitry University of Washington Box 351700 Seattle, WA 98195 Phone: 206-616-6882 Fax: 206-685-8665

I want to subset the dataframe based on certain values in a row. for each row in my dataframe if ANY one value of a particular set of columns satisfies cond append a logical value true at the end of the row else append a false at the end of the row in the end I want to be able to subset the whole data based on the appended true or false value. I could literally code like this, but I think

I am completely new to R, but have some bg in cs and stat. since R has an interactive programming environment, I thought I could write my command in a file and run it in batch mode in the Rgui. but it didnt work. I checked the doc. it said Rcmd BATCH inputfile. it didnt work either. Can someone help? thank you. thank you. also if you can shed some light on passing command line arguements (like