> -----Original Message----- > From: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] On Behalf Of Noah Silverman > Sent: Tuesday, August 04, 2009 8:40 PM > To: r help > Subject: [R] Counting things > > I've completed an experiment and want to summarize the results. > > There are two things I like to create. > > 1) A simple count of things from the data.frame with predictions > 1a) Number of predictions with probability greater than x
sum(logicalVector) returns the number of TRUEs in logicalVector, because it converts TRUE to 1 and FALSE to 0 before doing the sum. You will have to use na.rm=TRUE if there are NA's (missing values) in logical vector. Hence you get compute 1a with sum(probabilities>x) mean(probabilities>x) will give the proportion of times probabilities>x is TRUE. table(probabilities>x) will give a count of both the FALSEs and TRUEs. > 1b) Number of predictions with probability greater than > x that are really true sum(probabilities>x & label=="T") (I'm guessing that label is a character or factor vector with values "T" and "F".) Bill Dunlap TIBCO Software Inc - Spotfire Division wdunlap tibco.com > > In SQL, this would be, > "Select count(predictions) from data.frame where > probability > x" > "Select count(predictions) from data.frame where probability > x and > label ='T' " > > How can I do this one in R? > > > 2) I'd like to create what we call "binning". It is a simple list of > probability ranges and how accurate our model is. The idea is to see > how "true" our probabilities are. > for example > > range number of items mean(probability) true_accuracy > 100-90% 20 .924 > .90 > 90-80% 50 .825 > .84 > 80-70% 214 .75 > .71 > etc... > > It would be really great if I could also graph this! > > Is there any kind of package or way to do this in R > > Thanks! > > -N > > ______________________________________________ > 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.