[R] Vectorize 'eol' characters

[Prof Brian Ripley]

On Mon, 31 Oct 2011, Stefano Conti wrote:

> Dear R users,
>
> When dumping an R matrix object into a file -- typically via the 
> 'write.table' function -- the 'eol' option can be used to specify 
> the end-of-line character(s) which should appear at the end of each 
> row.
>
> However the argument to 'eol' seems to be restricted to have length 
> 1, whereas ideally I would like different rows to be written to file 
> each with its own end character string.  For instance:

That's not what 'eol' means.  It is the indicator of the end of line, 
so of course it is the same for every line.

>> test <- matrix(1:12, nrow=4); test
>     [,1] [,2] [,3]
> [1,]    1    5    9
> [2,]    2    6   10
> [3,]    3    7   11
> [4,]    4    8   12
>
>> write.table(test, file="test.txt", sep=" ", eol=paste(" test", 1:4, "\n", sep=""))
>
>> read.table(file="test.txt", sep=" ")
>  V1 V2 V3 test1
> 1  1  5  9 test1
> 2  2  6 10 test1
> 3  3  7 11 test1
> 4  4  8 12 test1
>
> whereas I would like the last column of the dump file to be "test1", 
> "test2", "test3", "test4".  Is there a way this could be achieved?

Hmn, you said it: 'the last column'.
Create what you want as the last column of your data frame: it wil 
then be written to the file as the last column.

The author of write.table.

> With many thanks in advance for your help, kind regards,
>
>
> --
> Dr Stefano Conti
> Statistics Unit (room #2A19)
> Health Protection Services
> HPA Colindale
> 61 Colindale Avenue
> London NW9 5EQ, UK
> tel: +44 (0)208-3277825
> fax: +44 (0)208-2007868
>
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-- 
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