[R] Convert a "by" list into a data frame

From: Tudor Bodea <gtg757i_at_mail.gatech.edu>
Date: Mon 27 Jun 2005 - 12:10:14 EST

Dear useRs,

Is there a way to convert a list generated by "by" command into a data frame? Or, more generally, are there any functions that operate on "by" lists? My "by" list consists of numeric vectors of equal length and the objective is to calculate the sum of the same index elements (i.e., column-wise sums). For example, if the "by" list were

Data_DF$CASE: 1
       IVTT     COST

[1,] 1 2
-------------------------- Data_DF$CASE: 2 IVTT COST
[1,] 2 4

I would like to finally obtain a numeric vector:

[1] 1.5 3

Thank you.

Tudor Dan Bodea
Georgia Institute of Technology
School of Civil and Environmental Engineering

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Received on Mon Jun 27 12:15:54 2005

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