[R] Novice question about getting data into R

Ted Byers r.ted.byers at gmail.com
Fri Sep 19 21:03:59 CEST 2008


Thanks one and all.

Actually, I used OpenOffice's spreadsheet to creat the csv file, but I have
been using it long enough to know to specify how I wanted it, and sometimes,
when that proves annoying, I'll use Perl to finess it the way I want it.

It seems my principle error was to assume that it would ignore the character
strings within the double quotes and determine fields based on the commas. 
Silvia's remarks about empty cells and blanks in the middle of column names
were right on the mark.

Tom, I appreciate the caveats you mention.  I am aware of the complications
of i18n, but they don't affect me much as my stuff is run exclusively in
Canada (pretty much the same norms as the US).  They don't affect me (in a
sense because I have manipuated data around such issues using perl in order
to satisfy the peculiarities of the software used on one project or another
- I deal with it almost as a matter of course, as long as I already know the
peculiarities of the software I am working with), and I have plenty of
experience moving data between spreadsheets, RDBMS such as MS SQL,
PostgreSQl, MySQL, and XML files, and have had to resort to unusual
delimiters in the past because of peculiarities in the data feed.  While I
have tonnes of experience developing software (C++, Java, FORTRAN, perl) I
only started playing with R a few months ago, and this is the first I have
had to import real data into it.  While the tutorials I found were useful,
it seems there are key tidbits of information I need scattered through the
documentation and I am finding it challenging to find the peculiarities of
R.

Thanks again one and all.

Ted



Tom Backer Johnsen wrote:
> 
> Silvia Lomascolo wrote:
>> 
>>> refdata =
>>> read.table("K:\\MerchantData\\RiskModel\\refund_distribution.csv",
>>> header
>>> = TRUE)
>> Error in scan(file, what, nmax, sep, dec, quote, skip, nlines,
>> na.strings, 
>> : 
>>   line 1 did not have 42 elements
>>> refdata =
>>> read.table("K:\\MerchantData\\RiskModel\\refund_distribution.csv")
>> Error in scan(file, what, nmax, sep, dec, quote, skip, nlines,
>> na.strings, 
>> : 
>>   line 2 did not have 42 elements
>> R interprets that you have 42 columns from the variable names. Do you?
>> See
>> if removing spaces between column names helps (e.g., "week.1" instead of
>> "week 1").  Also, because yours is a csv file, fields are separated by
>> comas.  You can either use the "read.csv" command instead of the
>> "read.table" (see ?read.table for details), or add the argument sep=","
>> to
>> tell R that fields are separated by comas.  You might also need to
>> specify,
>> if you have empty cells, what to do with them (e.g., na.strings="")
> 
> You are of course right about the NA's (missing values, empty cells) as 
> well as the possible blanks in the column names.  It might nevertheless 
> be a good idea for him to at least submit a few of the lines at the top 
> of the file.  A .csv file as generated by Excel on Windows is not 
> necessarily comma-separated.  That depends on the "list separator" 
> setting under "Regional Language Settings" found in the Control Panel. 
> On my machine, the list separator is a semicolon for a .csv file.  The 
> reason is simple, in Norway, the standard decimal separator is a comma, 
> and you do not want to confuse the system too much.  So, that particular 
> point is dependent on the settisngs for his locale (language, country).
> 
> Tom
>> 
>> 
>> 
>> 
> 
> 
> -- 
> +----------------------------------------------------------------+
> | Tom Backer Johnsen, Psychometrics Unit,  Faculty of Psychology |
> | University of Bergen, Christies gt. 12, N-5015 Bergen,  NORWAY |
> | Tel : +47-5558-9185                        Fax : +47-5558-9879 |
> | Email : backer at psych.uib.no    URL : http://www.galton.uib.no/ |
> +----------------------------------------------------------------+
> 
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