Hi On 9 Jul 2006 at 20:01, Daryl Manning wrote:
To: [email protected] From: Daryl Manning <[EMAIL PROTECTED]> Date sent: Sun, 9 Jul 2006 20:01:10 -0700 Subject: [R] How to get R to ignore certain values when analyzing a column in a data table ? > Apologies if this is in (one of the many) manuals somewhere... Trying > to switch to R from other stats programs. > > Basically, I have a large data table I've dumped from a DB, some of > the values which are nulls '-' which I've converted to zeros. I've > read it in using read.table fine. > > I want R to ignore the zero values when graphing or doing various > other calculations. > > Is there a way to do this ? > > I did try to use NA but kept getting errors that x must be numeric. What does str(your.data) says about your data? I presume it is factor. datafr <- data.frame(a=rnorm(10), b=rnorm(10)) datafr[3,1]<-0 > datafr$a [1] -0.1645236 -0.2533617 0.0000000 0.5566632 -0.6887557 - 0.7074952 0.3645820 0.7685329 -0.1123462 0.8811077 > mean(datafr$a) [1] 0.06444035 > datafr$a==0 [1] FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE FALSE FALSE > datafr$a[datafr$a==0] [1] 0 > datafr$a[datafr$a==0]<-NA > mean(datafr$a) [1] NA > mean(datafr$a, na.rm=T) [1] 0.07160039 > works OK. HTH Petr > > thanks in advance, > Daryl. > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html Petr Pikal [EMAIL PROTECTED] ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
