From: Zhang, Fan <fzhang_at_doubleclick.net>

Date: Fri 15 Jul 2005 - 03:02:35 EST

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Jul 15 03:11:22 2005

Date: Fri 15 Jul 2005 - 03:02:35 EST

Hello,

I have a dataframe which I read from a file:

df <- readtable(myFile);

The dataframe has 4 columns: "model", "count", "value" and "date" where
"model" and "date" are made of charactors and "count" and "value" are
numbers. An example is like:

model count value date

A 4 20.8 7/1/2005 A 3 10.2 7/2/2005 B 7 14.2 7/1/2005 B 1 6.2 7/2/2005 A 2 11 7/1/2005 B 9 65.2 7/2/2005

Now I want to get the total count and value for each model/date pair,
like

model count value date

A 6 31.8 7/1/2005 A 3 10.2 7/2/2005 B 7 14.2 7/1/2005 B 10 67.4 7/2/2005

Anyone can tell me how to do this?

Thanks.

Fan

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R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Jul 15 03:11:22 2005

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