Hello list members,
I'm looking for a way to force the results of a crosstabulation to be
square - that is, to include 0 values.
For example:
table(letters[1:4],letters[c(1:3,3)])
yields:
a b c
a 1 0 0
b 0 1 0
c 0 0 1
d 0 0 1
I would like to return:
a b c d
a 1 0 0 0
b 0 1 0 0
c 0 0 1 0
d 0 0 1 0
Any suggestions?
Thanks!
--
Manuel A. Morales
http://mutualism.williams.edu
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On 12/2/2006 8:26 PM, Manuel Morales wrote:> Hello list members, > > I'm looking for a way to force the results of a crosstabulation to be > square - that is, to include 0 values. > > For example: > > table(letters[1:4],letters[c(1:3,3)]) > > yields: > a b c > a 1 0 0 > b 0 1 0 > c 0 0 1 > d 0 0 1 > > I would like to return: > a b c d > a 1 0 0 0 > b 0 1 0 0 > c 0 0 1 0 > d 0 0 1 0 > > Any suggestions?Force the categories to be factors. > fletters <- factor(letters[1:4]) > table(fletters[1:4],fletters[c(1:3,3)]) a b c d a 1 0 0 0 b 0 1 0 0 c 0 0 1 0 d 0 0 1 0 The idea is that when you take subsets of factors, the levels stay the same, and table uses those levels for its categories. Duncan Murdoch
Use factors with specified levels.> lev <- letters[1:4] > table(factor(letters[1:4], levels = lev),factor(letters[c(1:3,3)], levels = lev)) a b c d a 1 0 0 0 b 0 1 0 0 c 0 0 1 0 d 0 0 1 0 -----Original Message----- From: r-help-bounces at stat.math.ethz.ch [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Manuel Morales Sent: Sunday, 3 December 2006 11:27 AM To: r-help at stat.math.ethz.ch Subject: [R] Force "square" crosstabulation Hello list members, I'm looking for a way to force the results of a crosstabulation to be square - that is, to include 0 values. For example: table(letters[1:4],letters[c(1:3,3)]) yields: a b c a 1 0 0 b 0 1 0 c 0 0 1 d 0 0 1 I would like to return: a b c d a 1 0 0 0 b 0 1 0 0 c 0 0 1 0 d 0 0 1 0 Any suggestions? Thanks! -- Manuel A. Morales http://mutualism.williams.edu