Tena koe Maria ?tapply
Specifically: tapply(yourData$PM, yourData$ID, median) HTH .... Peter Alspach > -----Original Message----- > From: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] On Behalf Of "María del > Pilar Márquez" > Sent: Thursday, 28 January 2010 7:06 a.m. > To: r-help@r-project.org > Subject: [R] median of grouped data > > Good morning, > I would like to know if is possible somebody can help me with > this please: > I would like to calculate the median of grouped data, this is > an example: > > ID PM > adt_01 25.255 > adt_01 225.36 > adt_01 14.2325 > adt_02 15 > adt_02 12.3 > adt_03 15.2 > adt_03 148.3 > adt_03 25.5 > adt_03 14.25 > > I need the median of adt_01, 02 and 03 , I know that I have > to split first my data and then ask for the median but the > code I have is not working. > > Thank you very much if you can help me with the code maria > > ______________________________________________ > 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.