[R] encodings (was Reading .csv file under linux)

[Prof Brian Ripley]

As a real-life example, package fdim is marked as being in latin2. 
However, ?fdim looks more plausible to me in latin1: I'm more confident 
about this as the original authors are Spanish which language is never (?) 
written in latin2, and I checked with a Spanish reader.

On Tue, 22 Jan 2008, Prof Brian Ripley wrote:

> On Wed, 23 Jan 2008, David Scott wrote:
>
>> On Tue, 22 Jan 2008, Prof Brian Ripley wrote:
>> 
>>> On Wed, 23 Jan 2008, David Scott wrote:
>>> 
>>>> 
>>>> I have encountered a problem with reading a .csv file on a linux box. I
>>>> can read the file on my windows machine (under XP) but on the linux box 
>>>> it
>>>> gives :
>>>> 
>>>>> patients <- read.csv("../Patients.csv", header = FALSE,
>>>> +                      col.names = patientsNames)
>>>> Error in type.convert(data[[i]], as.is = as.is[i], dec = dec,
>>>> na.strings = character(0)) :
>>>>   invalid multibyte string
>>>> Calls: read.csv -> read.table -> type.convert
>>>> Execution halted
>>>> 
>>>> I am running R 2.6.1 on both machines. I tried on another linux box
>>>> running 2.5.1 and got the same problem
>>>> 
>>>> I am guessing it is something to do with the character encoding. On the
>>>> linux box I have
>>>> 
>>>> LANG=en_US.UTF-8
>>> 
>>> So what encoding is the .csv file in?  Consider the example at the end of 
>>> ?file
>>>
>>>     ## examples of use of encodings
>>>     cat(x, file = file("foo", "w", encoding="UTF-8"))
>>>     # read a 'Windows Unicode' file including names
>>>     A <- read.table(file("students", encoding="UCS-2LE"))
>>> 
>>> and adapt accordingly (encoding = "CP1252" is the most likely value if 
>>> this works in English-language Windows).
>>> 
>> 
>> 
>> Thanks Brian for the super-quick, super-helpful reply. The encoding you 
>> suggested worked.
>> 
>> I found a workaround myself too---I guessed that some plus/minus signs 
>> might be the problem and replaced them and could read in the file.
>> That is just a kludge so I am using the encoding specification.
>> 
>> I am a total dunce when it comes to encodings though. How do you find the 
>> encoding of a file?
>
> You ask the person who gave it to you.  You can't in general tell, and e.g. 
> ISO-8859-1 and ISO-8859-2 are only distinguishable by someone who can read 
> the contents (if it is a human language).  If you have just the odd symbol 
> (e.g. degree sign or plus/minus) you can be completely stuck.
>
> 'file' on Linux can usually guess if a file is UTF-8 or ISO-8859-?, but not 
> of course what ? is.  But guesses are based on statistical patterns and are 
> good for text but not so good for data.
>
> -- 
> 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
>

-- 
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