Look at Encoding() on your two strings. The results are different, and
this seems to be the root of the problem. Adding encoding="latin1" to the
read.csv call is a workaround.
It looks like there is a problem in the use of the CHARSXP cache: if I
save the session then x0 == x becomes true when I reload it, even though
the encodings remain different.
I've found the immediate cause and will change this in R-patched shortly.
On Thu, 6 Nov 2008, Heinz Tuechler wrote:
Dear All!
Reading character strings containing an "umlaut" from a csv-file I find a (to
me) surprising behaviour in R 2.8.0, that I did not notice in R 2.7.2.
A comparison by "==" results in FALSE, while grep does find the aggreement.
See the example below.
The crucial line is x=="div 1-2 Veränderungen", with the result [1] FALSE in
R 2.8.0 but
[1] TRUE in R 2.7.2.
Thank you in advance for your help
Heinz Tüchler
##### in R 2.8.0 patched
x0 <- "div 1-2 Veränderungen" # define a character string
write.csv(x0, 'chr.csv', row.names=FALSE) # write a csv-file with one line
rm(x0)
x <- read.csv('chr.csv', skip=0, header=TRUE, as.is=TRUE)$x # read in
csv-file
x
x=="div 1-2 Veränderungen"
[1] FALSE
grep("div 1-2 Veränderungen", x)
[1] 1
grep("div 1-2 Veränderungen", x, value=TRUE)
[1] "div 1-2 Veränderungen"
unlink('chr.csv') # delete file
Version:
platform = i386-pc-mingw32
arch = i386
os = mingw32
system = i386, mingw32
status = Patched
major = 2
minor = 8.0
year = 2008
month = 11
day = 04
svn rev = 46830
language = R
version.string = R version 2.8.0 Patched (2008-11-04 r46830)
Windows XP (build 2600) Service Pack 2
Locale:
LC_COLLATE=German_Austria.1252;LC_CTYPE=German_Austria.1252;LC_MONETARY=German_Austria.1252;LC_NUMERIC=C;LC_TIME=German_Austria.1252
Search Path:
.GlobalEnv, package:stats, package:graphics, package:grDevices,
package:utils, package:datasets, package:methods, Autoloads, package:base
##### in R 2.7.2 patched
x0 <- "div 1-2 Veränderungen" # define a character string
write.csv(x0, 'chr.csv', row.names=FALSE) # write a csv-file with one line
rm(x0)
x <- read.csv('chr.csv', skip=0, header=TRUE, as.is=TRUE)$x # read in
csv-file
x
x=="div 1-2 Veränderungen"
[1] TRUE
grep("div 1-2 Veränderungen", x)
[1] 1
grep("div 1-2 Veränderungen", x, value=TRUE)
[1] "div 1-2 Veränderungen"
unlink('chr.csv') # delete file
Version:
platform = i386-pc-mingw32
arch = i386
os = mingw32
system = i386, mingw32
status = Patched
major = 2
minor = 7.2
year = 2008
month = 09
day = 02
svn rev = 46486
language = R
version.string = R version 2.7.2 Patched (2008-09-02 r46486)
Windows XP (build 2600) Service Pack 2
Locale:
LC_COLLATE=German_Austria.1252;LC_CTYPE=German_Austria.1252;LC_MONETARY=German_Austria.1252;LC_NUMERIC=C;LC_TIME=German_Austria.1252
Search Path:
.GlobalEnv, package:stats, package:graphics, package:grDevices,
package:utils, package:datasets, package:methods, Autoloads, package:base
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--
Brian D. Ripley, [EMAIL PROTECTED]
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
______________________________________________
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and provide commented, minimal, self-contained, reproducible code.
