[R] multiple bases to decimal (was: comparing two matrices)
Adrian Dusa
dusa.adrian at gmail.com
Sun Jan 21 13:39:33 CET 2007
Hi again,
I was contemplating the solution using base 3:
set.seed(3)
mat2 <- matrix(sample(0:2, 15, replace=T), 5, 3)
Extracting the line numbers is simple:
bases <- c(3, 3, 3)^(2:0) # or just 3^(2:0)
colSums(apply(mat2, 1, function(x) x*bases)) + 1
[1] 7 23 25 8 1
The problem is sometimes the columns have different number of levels, as in:
mat1 <- expand.grid(0:2, 0:2, 0:1)[,3:1]
Is there any chance to combine different bases in order to obtain the
corresponding line numbers?
I thought of something like:
bases <- c(3, 3, 2)^(2:0)
but it doesn't work (sigh).
Thanks for any hint,
Adrian
--
Adrian Dusa
Romanian Social Data Archive
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050025 Bucharest sector 5
Romania
Tel./Fax: +40 21 3126618 \
+40 21 3120210 / int.101
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