try this:
X <- factor(sample(c("A", "B", "C"), 10, TRUE), levels = c("A", "B",
"C"))
Y <- factor(sample(c("A", "B", "C"), 10, TRUE), levels = c("A", "B",
"C"))
#############
table(X, Y)
I hope it helps.
Best,
Dimitris
----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven
Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/16/336899
Fax: +32/16/337015
Web: http://www.med.kuleuven.be/biostat/
http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm
----- Original Message -----
From: "zhihua li" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Tuesday, June 21, 2005 2:46 PM
Subject: [R] how to count "associated" factors?
hi netters
Suppose I have a factor X, with 10 elements and 3 levels: A B B C A
C B A C
C .
It is easy to count the number of elements for each level:
tapply(X,X,length).
Now I have another factor Y, which formed a matrix with X:
X| A B B C A C B A C C
Y| B B C C C A A A B B
I wanna count the number of elements for each of these conditions:
when X=A
and Y=A; when X=A and Y=B; when X=A and Y=C; when X=B and Y=A; when
X=B and
Y=B; when X=B and Y=C; when X=C and Y=A; when X=C and Y=B; when X=C
and
Y=C.
The code I have written for this task is too complicated, involving
a lot
of for loops and if conditions. I believe there's some nice code
that can
do it far more efficiently. Can anyone give me a hint?
Thanks a lot!
--------------------------------------------------------------------------------
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______________________________________________
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https://stat.ethz.ch/mailman/listinfo/r-help
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