[R] newbie question: grouping rows

Augusto.Sanabria at ga.gov.au Augusto.Sanabria at ga.gov.au
Thu Mar 9 23:32:37 CET 2006


Have a look at "subset" specially the examples
at the end.

I use it a lot.

Hope it helps,


Augusto Sanabria. MSc, PhD.
Mathematical Modeller
Risk Research Group
Geospatial & Earth Monitoring Division
Geoscience Australia (www.ga.gov.au)
Cnr. Jerrabomberra Av. & Hindmarsh Dr.
Symonston ACT 2609
Ph. (02) 6249-9155

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Matthew Scholz
Sent: Friday, 10 March 2006 9:18 AM
To: r-help at stat.math.ethz.ch
Subject: [R] newbie question: grouping rows

Hi all,

I have a very simple question that I can't seem to find the answer to. How do
I extract rows that meet a certain criteria  from a data frame and group them
into a new data frame? For example, if I want to make a new data frame that
only includes rows of data for which the p values (given by one of the
columns in the data frame) are less than a certain value, how do I do this?
It seems that there should be a simple function that does this. I looked into
getGroups from the nmle package, but am not sure how to construct the form
argument correctly or even if it's the appropriate way to tackle this.

Thanks in advance of your answer,


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