Hi [EMAIL PROTECTED] napsal dne 03.01.2008 11:53:38:
> Hi all, > > Could someone please explain how can i efficientily query a data frame > with several factors, as shown below: > > --------------------------------------------------------------------------------------------------------- > Data frame: pt.knn > --------------------------------------------------------------------------------------------------------- > row | k.idx | step.forwd | pt.num | model | prev | value > | abs.error > 1 200 0 1 lm 09 > 10.5 1.5 > 2 200 0 2 lm 11 > 10.5 1.5 > 3 201 1 1 lm 10 > 12 2.0 > 4 201 1 2 lm 12 > 12 2.0 > 5 202 2 1 lm 12 > 12.1 0.1 > 6 202 2 2 lm 12 > 12.1 0.1 > 7 200 0 1 rlm 10.1 > 10.5 0.4 > 8 200 0 2 rlm 10.3 > 10.5 0.2 > 9 201 1 1 rlm 11.6 > 12 0.4 > 10 201 1 2 rlm 11.4 > 12 0.6 > 11 202 2 1 rlm 11.8 > 12.1 0.1 > 12 202 2 2 rlm 11.9 > 12.1 0.2 > ---------------------------------------------------------------------------------------------------------- > > k.idx, step.forwd, pt.num and model columns are FACTORS. > prev, value, abs.error are numeric > > I need to take the mean value of the numeric columns (prev, value and > abs.error) for each k.idx and step.forwd and model. So: rows 1 and 2, > 3 and 4, 5 and 6,7 and 8, 9 and 10, 11 and 12 must be grouped > together. aggregate(numeric.columns, list(factors), mean) > > Next, i need to plot a boxplot of the mean(abs.error) of each model > for each k.idx. Maybe boxplot(split(abs.error, interaction(k.idx, model))) Regards Petr > I need to compare the abs.error of the two models for each step and > the mean overall abs.error of each model. And so on. > > I read the manuals, but the examples there are too simple. I know how > to do this manipulation in a "brute force" manner, but i wish to learn > how to work the right way with R. > > Could someone help me? > Thanks in advance. > > José Augusto > Undergraduate student > University of São Paulo > Business Administration Faculty > > ______________________________________________ > 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.
