Hallo [EMAIL PROTECTED] napsal dne 21.05.2008 09:42:40:
> Hi, > > I just started using R for about one week and I have few problems. > > i)I have a problem in finding right function to convert a table of natural > numbers to bitwise. For a simple example; > > I have the below table:- > > Column Col1 Col2 Col3 > Sample1 5 7 10 > Sample2 0 2 1 > Sample3 4 0 0 > > > Supposedly i wanted to convert to :- > > > Column Col1 Col2 Col3 > Sample1 1 1 1 > Sample2 0 1 1 > Sample3 1 0 0 data<-read.table("clipboard", header=T If data is your data frame, data.bit<-data.frame(column=data[,1],(data[,-1]>0)*1) > > ii)Besides, I would like to create a formula of Sum(3*(Element in each > column for a row))..does it equivalent to 3*(data[1:3,1:2]) in this case?or > I need to have Sum(3*(data[1:3,1:2])). Basically I wanted to mutliply each > element of column table of a row and sum it up. Rather complicated. > 3*(data[1:3,2:3]) Col1 Col2 1 15 21 2 0 6 3 12 0 > sum(3*(data[1:3,2:3])) [1] 54 Works but I am suspicious that you wont something else. > > iii)I would also like to know how to insert an if else statement where in > the above case, I wanted to check if data[1:3,] > returns me 1 or 0, it will execute some calculations. > I refer to the R intro pdf and it mentioned using if (expr_1 ) expr_2 else > expr_3. Does that mean if(data[1:3,1:2])>0 output[1:3,1:2]=0 > else output[1:3,1:2]="100". If I did this command, how does R knows which > row and column to map the output with? If ... else ... is usually for working as programming steps ifelse(..., ..., ...) works with objects and is parts. You shall think first how to do your calculations with whole objects, it is usually more effective. Regards Petr > > Please advise. Appreciate alot. Thanks. > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. ______________________________________________ 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.