Transforming matrix

Dear Ramzi,

If you have your TRUE/FALSE values in m1, then do

mode(m1) <- "numeric".

This is probably not the best way but it seems to work.


Ram?n

hi everybody,
anyone knows how we can transform a binary matrix with TRUE and FALSE to 0
and 1 without looping? Thx



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Ram?n D?az-Uriarte
Bioinformatics Unit
Centro Nacional de Investigaciones Oncol?gicas (CNIO)
(Spanish National Cancer Center)
Melchor Fern?ndez Almagro, 3
28029 Madrid (Spain)
Fax: +-34-91-224-6972
Phone: +-34-91-224-6900

http://bioinfo.cnio.es/~rdiaz

Assuming that TRUE==1 and FALSE==0, just do

 > x = matrix(c(TRUE,TRUE,FALSE,FALSE),2,2)
 > x
      [,1]  [,2]
[1,] TRUE FALSE
[2,] TRUE FALSE
 > as.numeric(x)
[1] 1 1 0 0
 > array(as.numeric(x),dim=dim(x))
      [,1] [,2]
[1,]    1    0
[2,]    1    0

hi everybody, 
anyone knows how we can transform a binary matrix with TRUE and FALSE to 0 and 1 without looping? 
Thx 



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At 15:56 10/04/2003 +0200, vous avez ?crit:

hi everybody,
anyone knows how we can transform a binary matrix with TRUE and FALSE to 0 
and 1 without looping?
Thx

I guess you mean:

  TRUE ==> 1
FALSE ==> 0

as this is the rule when logicals are converted into numerics. Then, if M 
is your matrix, you can do:

mode(M) <- "numeric"

If you actually want:

  TRUE ==> 0
FALSE ==> 1

then:

M <- !M
mode(M) <- "numeric"

should do it.

HTH

EP

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Dear Ramzi,

If you have your TRUE/FALSE values in m1, then do

mode(m1) <- "numeric".

Except that TRUE is 1 and FALSE is 0. The original question was:

anyone knows how we can transform a binary matrix with TRUE and FALSE to 0
and 1 without looping? 

which could imply they want TRUE mapped to 0, and FALSE to 1, which is 
done with '1-':

 > foo
       [,1] [,2]  [,3]  [,4]  [,5]
[1,] FALSE TRUE FALSE FALSE  TRUE
[2,]  TRUE TRUE  TRUE FALSE FALSE

 > 1-foo
      [,1] [,2] [,3] [,4] [,5]
[1,]    1    0    1    1    0
[2,]    0    0    0    1    1
 >

  R will convert TRUE to 1 and FALSE to 0 in a numeric context:

 > foo*1
      [,1] [,2] [,3] [,4] [,5]
[1,]    0    1    0    0    1
[2,]    1    1    1    0    0

Baz

A <- array(c(T,F,F,T), dim=c(2,2))

> A+0
      [,1] [,2]
[1,]    1    0
[2,]    0    1

How's this?
Spencer Graves

hi everybody, 
anyone knows how we can transform a binary matrix with TRUE and FALSE to 0 and 1 without looping? 
Thx 



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If you have your TRUE/FALSE values in m1, then do

mode(m1) <- "numeric".

This is probably not the best way but it seems to work.

That maps TRUE to 1 and FALSE to 0, and I read the request as for the 
reverse.

ifelse(m1, 0, 1) is probably the most transparent way.

On Thursday 10 April 2003 15:56, Ramzi Feghali wrote:

hi everybody,
anyone knows how we can transform a binary matrix with TRUE and FALSE to 0
and 1 without looping? Thx

Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595