Adding dash-lines in R tables

On May 22, 2011, at 7:47 AM, Axel Urbiz wrote:

is it possible to add dash lines to tables or matrices when they are
printed? An example of what I'm looking for is this:

library(Design)
y <- sample(c(0,1),100, replace = TRUE)
x <- rnorm(100)
summary(y ~ x)

There is a method for summary on formula objects found by typing

methods(summary) ? # didn't find the answer looking at code of
summary.formula.

Then there is a print method for summary.formula objects>

methods(print)
# examine the 3 print.summary. .... methods
# didn't find the answer there, either, but did notice that the
# function `print.char.matrix` was being used near the end of the code

M <- matrix(letters[1:10], 2)
print.char.matrix(M)

+-+-+-+-+-+
|a|c|e|g|i|
+-+-+-+-+-+
|b|d|f|h|j|
+-+-+-+-+-+

It is in package Hmisc and its behavior is documented:

?print.char.matrix

print.char.matrix( table(sample(1:10, 100, replace=TRUE) ) ?)

+--+--+
| 1|12|
+--+--+
| 2| 6|
+--+--+
| 3|11|
+--+--+
| 4|13|
+--+--+
| 5|12|
+--+--+
| 6| 7|
+--+--+
| 7| 8|
+--+--+
| 8| 8|
+--+--+
| 9|14|
+--+--+
|10| 9|
+--+--+

--

David Winsemius, MD
West Hartford, CT