[R] Computting statistics on a matrix with 2 factor column
Marc Mamin
M.Mamin at intershop.de
Tue Jun 8 15:38:10 CEST 2004
Hello,
I suppose this is a basic question but couldn't find a solution.:
I have a large matrix with let say 3 columns:
V1 V2 V3
a x 2
a x 4
a y 8
b z 16
and I want to compute some statistics based on
the levels resulting form the combination of the two first columns
e.g.:
SUM->
V1 V2 V3
a x 6
a y 8
b z 16
Thanks for your hints .
Marc
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