R help - Apr 2008 - How to replace German umlauts in strings?

Dear R-users,

I have a file containing names of German students. These names  
contain the characters "?", "?" or "?" (German
umlauts). I use
read.table() to read the file and let's assume the table is then  
stored in a variable called "data". The names are then contained in  
the first column, i.e. data[,1]. Now if I simply display the variable  
"data", I see, that "?" is replaced by \x8a, "?"
is replaced by \x9a
and so forth. Now, I would like to have these characters replaced by  
their LaTeX (or TeX) equivalents, meaning \x8a should be replaced by  
\"a, \x9a should be replaced by \"o and so forth. I tried a lot,  
especially with gsub(), however, the backslashes cause problems and I  
do not know how to get this to work. The data.frame should then be  
written to a file without destroying the replaced substrings (so that  
indeed \"a appears in the file for \x8a). Is this possible?

Here is a minimal example:
data=data.frame(names=c("Bj\x9arn","S\x9aren"),points=c 
(10,20),stringsAsFactors=F)
data[1,1]=gsub('\\x9a','\\"o',data[1,1]) #does not work!
(neither do
similar calls)

Thanks in advance

Marius

On 10.04.2008, at 18:03, Hofert Marius wrote:
> I have a file containing names of German students. These names
> contain the characters "?", "?" or "?"
(German umlauts). I use
> read.table() to read the file and let's assume the table is then
> stored in a variable called "data". The names are then contained
in
> the first column, i.e. data[,1]. Now if I simply display the variable
> "data", I see, that "?" is replaced by \x8a,
"?" is replaced by \x9a
> and so forth. Now, I would like to have these characters replaced by
> their LaTeX (or TeX) equivalents, meaning \x8a should be replaced by
> \"a, \x9a should be replaced by \"o and so forth. I tried a lot,
> especially with gsub(), however, the backslashes cause problems and I
> do not know how to get this to work. The data.frame should then be
> written to a file without destroying the replaced substrings (so that
> indeed \"a appears in the file for \x8a). Is this possible?
>
> Here is a minimal example:
> data=data.frame(names=c("Bj\x9arn","S\x9aren"),points=c
> (10,20),stringsAsFactors=F)
> data[1,1]=gsub('\\x9a','\\"o',data[1,1]) #does not
work! (neither do
> similar calls)
Try this:

gsub('\\x9a','\\"o',m, perl = TRUE, useBytes = TRUE)

Cheers,

--Hans