[R] Using read.table to read file created with read.table and qmethod = "escape"

David Winsemius dwinsemius at comcast.net
Thu Apr 8 17:01:44 CEST 2010

On Apr 8, 2010, at 10:01 AM, Hadley Wickham wrote:

>>> Can write.table and read.table really be so asymmetric?
>> write() is a wrapper for cat() and read() is a wrapper for scan()  
>> so the
>> question should really be can cat() and scan() be so asymmetric.  
>> Looking at
>> their help pages, I would say that at least some degree of  
>> asymmetry is
>> plausible. Perhaps using save() with load() , or dput() with  
>> dget(), which
>> are pairings that promise to have symmetry?
> Why should I have to care about the internal implementation details?
> This is one of the things that really frustrates me (and other new
> users of R) - read.table/write.table and read.csv/write.csv are named
> symmetrically, but do not work symmetrically.

I hope you won't take it amiss if I think it's great that you (in  
particular) get frustrated. You have already turned frustrations in  
other areas into productivity tools. I do have one further observation  
on this one that extends my earlier suggestion regarding the fact that  
this semi-strange behavior was a factor-type related issue of  
asymmetry rather than a character-type one:

 > df <- data.frame(a = "a\"b", v = 4, z = "this is: A, B, C",  
 > write.csv(df, "test.csv", row.names = FALSE)
 > df2<- read.csv("test.csv",  header=TRUE, stringsAsFactors=FALSE)
 > df2
     a v                z
1 a"b 4 this is: A, B, C
 > df2$a
[1] "a\"b"

Might I inquire if anyone know why displaying the dataframe version of  
the "a" element is different on the console from the vector version? I  
think it related to this behavior:

 > df2[[1]]
[1] "a\"b"
 > df2[1]
1 a"b

> Hadley
> -- 
> Assistant Professor / Dobelman Family Junior Chair
> Department of Statistics / Rice University
> http://had.co.nz/

David Winsemius, MD
West Hartford, CT

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