Data aggregation

?tapply

You should have encountered this already in most basic R tutorials.
Have you gone through any? If not, you should. In particular,you need
to learn about R's basic data structures (e.g. data frames).

Alternatively, the dplyr package has many elegant tools for this sort
of thing. You might do well to learn it instead or in addition to the
*apply type operations of base R.

Finally, I should ask: is this homework? This list tries to implement
a no homework policy.

Cheers,
Bert


Bert Gunter

"The trouble with having an open mind is that people keep coming along
and sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )

Dear All:
I have a data frame with 3 columns: "Regime", "Industry", and "Cost".
I want to sum the value of "Cost" for each industry and "Regime".
Example:

The data frame is:
Regime, Industry, Cost
10, 01, 370
11, 01, 400
10, 02, 200
10, 01, 500
11, 02, 60
10, 02, 30

I want the following output:
01, 10, 870
01, 11, 400
02, 10, 230
02, 11, 600

Can you please help me on this? Paolo

        [[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.