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NA problem with aggregate

To: <s-news@lists.biostat.wustl.edu>
Subject: NA problem with aggregate
From: "ONKELINX, Thierry" <Thierry.ONKELINX@inbo.be>
Date: Fri, 25 Nov 2005 13:36:07 +0100
Thread-index: AcXxvM6rZvKw04UJSHmQkaTinLU/oQ==
Thread-topic: NA problem with aggregate

Dear listers,

 

I’m working with a data frame with 6 columns. The first column indicates the year (ranging from 1993 until present) and the other ones the measurements at different locations. For each year there are several measurements and some of them are missing (NA). I need to sum the measurements in each column by year. The aggregate function should do the trick but the NA’s our troubling me.

 

The command:

aggregate(CiVi22), by = list(CiVi22$Year), FUN = sum, na.rm = T)

 

The output:

     Group.1      X11 X14 X15 X16 X21

1993    1993       NA  NA  NA  NA  NA

1994    1994 3745.594  NA  NA  NA  NA

1995    1995       NA  NA  NA  NA  NA

1996    1996       NA  NA  NA  NA  NA

1997    1997       NA  NA  NA  NA  NA

1998    1998       NA  NA  NA  NA  NA

1999    1999       NA  NA  NA  NA  NA

2000    2000       NA  NA  NA  NA  NA

2001    2001       NA  NA  NA  NA  NA

2002    2002       NA  NA  NA  NA  NA

2003    2003       NA  NA  NA  NA  NA

2004    2004       NA  NA  NA  NA  NA

 

This output is correct for the same command but without the na.rm parameter (or with na.rm = F). Including na.rm = T doesn’t seem to effect the sum function although it should. Any ideas about what’s going wrong?

 

Thank you in advance.

 

Thierry

--------------------------------------------------------
ir. Thierry Onkelinx
Instituut voor Bosbouw en Wildbeheer (Institute for Forestry and Game Management)
Team Biometrie, methodologie en kwaliteitszorg
Gaverstraat 4
9500 Geraardsbergen
Belgium
tel. + 32 54/436 185
fax. + 32 54/436 160
Thierry.Onkelinx@inbo.be
http://ibw.inbo.be

 

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