R help - Sep 2009 - Simple question about error on CSV import

I have a substantial CSV to import but can't seem to import even the
simplest CSV.

I'm running the latest stable REvolution R on OS X if that is pertinent.

Here's the contents of a simple test2.csv CSV file:

#,Status,Project  
5842,New,Test
> snortalerts = read.table( "/Users/lcox/Documents/test2.csv",
header=TRUE,
> sep=",", row.names="#")
Error in data[[rowvar]] : attempt to select less than one element

I can't see how it could get any more simple, yet it doesn't work. 
I'm
obviously missing something basic, but based on the error, I can't see what
it is.

Landon
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esawdust wrote:
> 
> Here's the contents of a simple test2.csv CSV file:
> 
> #,Status,Project  
> 5842,New,Test
> 
>> snortalerts = read.table( "/Users/lcox/Documents/test2.csv",
header=TRUE,
>> sep=",", row.names="#")
> Error in data[[rowvar]] : attempt to select less than one element
> 
> Landon
> 
Figured out the answer, though it wasn't obvious (to me anyway).  The symbol
"#" used as the first column label was the problem.   I changed that
to be
"id" and changed the read.table to be:

snortalerts <- read.table( "/Users/lcox/Documents/test2.csv",
header=TRUE,
sep=",", row.names="id")

and it worked fine.  
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> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of esawdust
> Sent: Tuesday, September 01, 2009 8:53 AM
> To: r-help at r-project.org
> Subject: [R] Simple question about error on CSV import
> 
> 
> 
> I have a substantial CSV to import but can't seem to import even the
> simplest CSV.
> 
> I'm running the latest stable REvolution R on OS X if that is 
> pertinent.
> 
> Here's the contents of a simple test2.csv CSV file:
> 
> #,Status,Project  
> 5842,New,Test
> 
> > snortalerts = read.table( 
> "/Users/lcox/Documents/test2.csv", header=TRUE,
> > sep=",", row.names="#")
> Error in data[[rowvar]] : attempt to select less than one element
> 
> I can't see how it could get any more simple, yet it doesn't 
> work.  I'm
> obviously missing something basic, but based on the error, I 
> can't see what
> it is.
Using '#' for the initial column name presents 2 problems:
   (a) # is the default comment character so that line is
       ignored.  Add the read.table argument comment.char=""
       to take care of that.
   (b) It looks like the column names are converted to legal
       R names before the row.names="name" is processed
       and the "#" is not legal so it becomes something random
       like "X.".  If you turn off this conversion to legal names
       with check.names=FALSE then things will work.  It
       might be better to use the index of the row.names column
       instead of the name, as in row.names=1.

E.g.,
> t<-"#,Status,Project\n5842,New,Test\n"
> read.table(textConnection(t), header=TRUE, sep=",",
comment.char="",
check.names=FALSE, row.names="#")
     Status Project
5842    New    Test
> read.table(textConnection(t), header=TRUE, sep=",",
comment.char="",
row.names=1)
     Status Project
5842    New    Test

Bill Dunlap
TIBCO Software Inc - Spotfire Division
wdunlap tibco.com 
 
> Landon
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thank you all for the quick responses and helpful explanations.  I'm just
getting started with R, so I'll get tripped up by some of this until I get
in the groove.

Thanks again,

Landon
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