Message-ID: <43F0CFEF.3070900@inf.ed.ac.uk>
Date: 2006-02-13T18:29:03Z
From: Roger Levy
Subject: indexing via a character matrix?
Hi,
Is it possible to index via a character matrix? For example, I would
like to do the following:
cont.table <- table(df1$A,df1$B) # df1 a data frame with factors A and B
cont.table[cbind(df2$A,df2$B)] # df2 a smaller data frame with some
# pairings of values for A and B
but the second step does not work -- I guess that matrices to be used
for indexing this way must be numeric. Is there a way to index multiple
character tuples out of a contingency table without resorting to writing
loops?
Many thanks,
Roger Levy