[Rd] Bug Report: read.table with UTF-8 encoded file imports infinity symbol as Integer 8

[Tomas Kalibera]

I can reproduce this behavior on my Windows 10 system in RGui (cp1252): 
when I paste the Unicode infinity symbol into the console, it is treated 
as number 8. This is caused by Windows "best fit" default behavior in 
conversion of unicode characters to characters in the current native 
encoding: at some point in the past, 8 has been chosen as a good fit for 
infinity in Windows. In my scenario, the conversion is invoked by RGui 
before returning the input to the main R loop, even before the input 
gets to the parser. In principle, we could change this particular 
conversion in RGui to avoid the substitution. RGui uses "\uxxxx" escapes 
to pass characters that cannot be represented, this is why e.g. the 
Cyrillic Zhe \u0436 worked, so we could tell Windows not to do the 
substitution and pass "\u221e" for Infinity, and then the string after 
being processed by the parser will be represented in UTF-8 inside R and 
could be e.g. printed by the RGui console. That is something that could 
be considered, but it will not solve the main problem and it may 
actually cause trouble to users who are used to such substitutions 
(especially when the substitutions are more intuitive, but, that may be 
a matter of opinion).

The main problem is that in normal use, sooner or later R will get to 
the point when it will need to do the conversion to native encoding, and 
in some context where "\uxxxx" escapes will not be possible. One cannot 
reliably work with strings in R that cannot be represented in the 
current native encoding (except when one knows precisely how to avoid 
the conversion in some specific task, but that may be brittle; so the 
best-fit substitution might in principle help here). This problem does 
not exist on Unix/macOS systems where the current native encoding is 
UTF-8 these days, so today it only exists on Windows where UTF-8 cannot 
be the current native encoding. As has been discussed before, even 
though we could rewrite in principle all calls to Windows API to use 
Unicode and have all strings in UTF-8 in R, we would still have problems 
when interfacing with packages that assume strings are in current native 
encoding (without checking), so this problem won't be easy to fix.

Best,
Tomas

On 2/7/19 3:10 PM, Daniel Possenriede wrote:
> There seems to be something odd with "∞" on Windows (and not only with
> read.table)
> In native encoding (cp-1252 in my case), "∞" gets converted to "8"
>
> x <-  "∞"
> Encoding(x)
> #> [1] "unknown"
> print(x)
> #> [1] "8"
> charToRaw(x)
> #> [1] 38
>
> "∞" is indeed "8"
>
> identical(x, "8")
> #> [1] TRUE
>
> Everything seems fine if  "∞" is UTF-8 encoded.
>
> y <- "\u221E"
> Encoding(y)
> #> [1] "UTF-8"
> print(y)
> #> [1]  "∞"
> charToRaw(y)
> #> [1] e2 88 9e
>
> Unless the string is converted back to native encoding.
>
> format(y)
> #> [1] "8"
>
> This ought to be "<U+221E>", equivalently to
>
> format("∝")
> #> [1] "<U+221D>"
>
> Session Info:
>
> si <- sessionInfo()
> si$running
> #> [1] "Windows 10 x64 (build 17134)"
> si$R.version$version.string
> #> [1] "R version 3.5.2 (2018-12-20)"
> si$locale
> #> [1]
> "LC_COLLATE=German_Germany.1252;LC_CTYPE=German_Germany.1252;LC_MONETARY=German_Germany.1252;LC_NUMERIC=C;LC_TIME=German_Germany.1252"
>
>
>
> Am Do., 7. Feb. 2019 um 14:33 Uhr schrieb David Byrne <
> david.byrne222 using gmail.com>:
>
>> I can confirm that it doesn't happen on Ubuntu 18.04.1 so Peter is
>> most likely correct; it looks like its Windows specific.
>>
>> On Thu, 7 Feb 2019 at 12:55, peter dalgaard <pdalgd using gmail.com> wrote:
>>> This doesn't seem to be happening on MacOS, neither in Terminal nor
>> RStudio, (R 3.5.1, R-devel, R-patched). So probably Windows specific.
>>> -pd
>>>
>>>> On 7 Feb 2019, at 11:17 , David Byrne <david.byrne222 using gmail.com>
>> wrote:
>>>> Bug
>>>> Using read.table(file, encoding="UTF-8") to import a UTF-8 encoded
>>>> file containing the infinity symbol (' ∞ ') results in the infinity
>>>> symbol imported as the number 8. Other Unicode characters seem
>>>> unaffected, example, Zhe: ж
>>>>
>>>> Expected Behavior:
>>>> The imported data.frame should represent the infinity symbol as the
>>>> expected 'Inf' so that normal mathematical operations can be processed
>>>>
>>>> Stack Overflow Post:
>>>> I created a question on Stack Overflow where one other member was able
>>>> to reproduce the same issues I was having. This question can be found
>>>> at:
>>>>
>> https://stackoverflow.com/questions/54522196/r-read-table-with-utf-8-encoded-file-reads-infinity-symbol-as-8-int
>>>> Method to Reproduce - 1:
>>>> A simple method to reproduce this issues is to use R-Studio: In the
>>>> console, type the following:
>>>>> read.table(text=" ∞", encoding="UTF-8")
>>>> The result should be a data.frame with a single value of '8'
>>>>
>>>> Repeating the same with ж Results in correct expected behavior
>>>>
>>>> Method to Reproduce - 2:
>>>> Create a .csv file containing the infinity and Zhe characters (I have
>>>> attached the file for convenience, hopefully it is no rejected by your
>>>> email service). Launch an interactive session using
>>>>
>>>>> r --vanilla
>>>> Enter the following statement taking care to replace the
>>>> <path-to-file> with the appropriate one:
>>>>
>>>>> read.table("<path-to-file>/unicode_chars.csv", sep=",",
>> encoding="UTF-8")
>>>>
>>>> This should result in a two element data.frame; the first being the
>>>> incorrect value of 8 with an additional <U+FEFF> and the second the
>>>> correct value of Zhe.
>>>>
>>>> Note the additional <U+FEFF> prefixed to the front of the '8'. This
>>>> appears to be a hidden character for the purposes of letting editors
>>>> know the encoding. The following link has some explanation however, it
>>>> states this is caused by excel. The file I created was done so using
>>>> notepad and not Excel.
>>>>
>>>>
>> https://medium.freecodecamp.org/a-quick-tale-about-feff-the-invisible-character-cd25cd4630e7
>>>> System Details:
>>>> OS:
>>>>> Windows 10.0.17134 Build 17134
>>>>
>>>> R Version:
>>>>> platform       x86_64-w64-mingw32
>>>>> arch           x86_64
>>>>> os             mingw32
>>>>> system         x86_64, mingw32
>>>>> status
>>>>> major          3
>>>>> minor          4.1
>>>>> year           2017
>>>>> month          06
>>>>> day            30
>>>>> svn rev        72865
>>>>> language       R
>>>>> version.string R version 3.4.1 (2017-06-30)
>>>>> nickname       Single Candle
>>>> ______________________________________________
>>>> R-devel using r-project.org mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>> --
>>> Peter Dalgaard, Professor,
>>> Center for Statistics, Copenhagen Business School
>>> Solbjerg Plads 3, 2000 Frederiksberg, Denmark
>>> Phone: (+45)38153501
>>> Office: A 4.23
>>> Email: pd.mes using cbs.dk  Priv: PDalgd using gmail.com
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
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