[R] newbie question: grouping rows

Vayssières, Marc marcv at water.ca.gov
Thu Mar 9 23:39:08 CET 2006



-----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: Thursday, March 09, 2006 2:18 PM
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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