Hi, With a data such as: > z = data.frame(a = 1:5, b=10*a, c = c("a", "a", "b", "b", "b") ) * a b c* *1* 10 *a* *2* 20 *a* 3 *30* *b* 4 *40* *b* 5 *50* *b*
Can anyone suggest a way to select [1, 2, 30, 40, 50], ie. using column "c" to specify which column is selected for each row. Many thanks G [[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.