R help - Jul 2002 - colClasses = "logical" produces all FALSE when input is 1/0

It seems to me that colClasses = "logical" in read.table produces
incorrect results when
the input file has `1' and `0' in it. Although, it is perhaps just as
likely
that I am misunderstanding the documentation.

Here is a simple example:
> file.show("test.txt")
x
1
0
1
> read.table("test.txt", header = TRUE)
  x
1 1
2 0
3 1

This result is fine.
> read.table("test.txt", header = TRUE, colClasses =
"character")
  x
1 1
2 0
3 1

This one also. However, I think that this result is wrong:
> readtable("test.txt", header = TRUE, colClasses =
"logical")
      x
1 FALSE
2 FALSE
3 FALSE

I would have expected:

      x
1 TRUE
2 FALSE
3 TRUE

Is there a way to get what I expected? Alas, I can't quite make out what
read.table is doing in this context.
> R.version
         _                   
platform sparc-sun-solaris2.6
arch     sparc               
os       solaris2.6          
system   sparc, solaris2.6   
status                       
major    1                   
minor    5.1                 
year     2002                
month    06                  
day      17                  
language R                   
> 
Any suggestions would be much appreciated. 

Regards,

Dave Kane
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On Tue, 23 Jul 2002, David Kane  <David Kane wrote:
> It seems to me that colClasses = "logical" in read.table produces
incorrect results when
> the input file has `1' and `0' in it. Although, it is perhaps just
as likely
> that I am misunderstanding the documentation.
[ ...  ]
> This one also. However, I think that this result is wrong:
>
> > readtable("test.txt", header = TRUE, colClasses =
"logical")
>       x
> 1 FALSE
> 2 FALSE
> 3 FALSE
Why?  0 and 1 are not valid values for a logical variable.
> I would have expected:
>
>       x
> 1 TRUE
> 2 FALSE
> 3 TRUE
>
> Is there a way to get what I expected?
Read as it as character or integer and convert later.
> Alas, I can't quite make out what read.table is doing in this context.
It is using scan():
> scan(what=logical(0))
1: 0 1 0
4:
Read 3 items
[1] FALSE FALSE FALSE

Anything other than T or TRUE is taken as false.  Perhaps it would have
confused you less if we had thrown an error.

-- 
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 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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