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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