R help - Apr 2006 - png overwrites upper/lower case filenames

Dear R users,

when I create files with the png graphics device, it overwrites existing 
files which differ concerning upper/lower case file names.
For example, I want to create four files named "a.png",
"A.png", "b.png"
and "B.png" which contain the corresponding letters:

png("a.png")
plot(1, type="n")
text(1, label="a")
dev.off()

png("A.png")
plot(1, type="n")
text(1, label="A")
dev.off()

png("B.png")
plot(1, type="n")
text(1, label="B")
dev.off()

png("b.png")
plot(1, type="n")
text(1, label="b")
dev.off()

These commands create a file named "a.png" which contains the letter
"A"
and a file named "B.png" which contains the letter "b".
The old file name is retained, but overwritten with the output of the 
new png device with the same case-insensitive file name.
I'm sure I missed something. Can anyone tell me how to create files 
whith case-sensitive names with the same letters?

R version 2.2.1, 2005-12-20, i386-pc-mingw32

Regards,
Timo

-- 
Timo Becker
Phonetics
Austrian Academy of Sciences
Acoustics Research Institute

*on Windows*

This is how the Windows file system works.  You cannot have a.png and 
A.png in a directory on a Windows file system.  If you unlink() the file
with the clashing name it will create it with the case you want (but since 
asking Windows for "B.png" will give you "b.png", does it
matter?).

On Tue, 11 Apr 2006, Timo Becker wrote:
> Dear R users,
>
> when I create files with the png graphics device, it overwrites existing
> files which differ concerning upper/lower case file names.
> For example, I want to create four files named "a.png",
"A.png", "b.png"
> and "B.png" which contain the corresponding letters:
>
> png("a.png")
> plot(1, type="n")
> text(1, label="a")
> dev.off()
>
> png("A.png")
> plot(1, type="n")
> text(1, label="A")
> dev.off()
>
> png("B.png")
> plot(1, type="n")
> text(1, label="B")
> dev.off()
>
> png("b.png")
> plot(1, type="n")
> text(1, label="b")
> dev.off()
>
> These commands create a file named "a.png" which contains the
letter "A"
> and a file named "B.png" which contains the letter "b".
> The old file name is retained, but overwritten with the output of the
> new png device with the same case-insensitive file name.
> I'm sure I missed something. Can anyone tell me how to create files
> whith case-sensitive names with the same letters?
>
> R version 2.2.1, 2005-12-20, i386-pc-mingw32
>
> Regards,
> Timo
>
>
-- 
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

Timo Becker wrote:
> Dear R users,
> 
> when I create files with the png graphics device, it overwrites existing 
> files which differ concerning upper/lower case file names.
> For example, I want to create four files named "a.png",
"A.png", "b.png"
> and "B.png" which contain the corresponding letters:
> 
> png("a.png")
> plot(1, type="n")
> text(1, label="a")
> dev.off()
> 
> png("A.png")
> plot(1, type="n")
> text(1, label="A")
> dev.off()
> 
> png("B.png")
> plot(1, type="n")
> text(1, label="B")
> dev.off()
> 
> png("b.png")
> plot(1, type="n")
> text(1, label="b")
> dev.off()
> 
> These commands create a file named "a.png" which contains the
letter "A"
> and a file named "B.png" which contains the letter "b".
> The old file name is retained, but overwritten with the output of the 
> new png device with the same case-insensitive file name.
> I'm sure I missed something. Can anyone tell me how to create files 
> whith case-sensitive names with the same letters?

You cannot on Windows. This is an OS but not an R issue.

Uwe Ligges

> R version 2.2.1, 2005-12-20, i386-pc-mingw32
> 
> Regards,
> Timo
>