R help - Aug 2008 - How to handle "~" character after csv importation

Dear R users,

I have to import some csv files in which column headers contain the 
character "~". Following the following import call, the character
seems
to be replaced by dots in the column names of my data frame. Plus, I 
cannot query names(mydata) to find the column index which header should 
contain "~" or "."

 > mydata <- data.frame(read.table("mycsv.csv", sep =
",", header =
TRUE, na.strings = ".", as.is = TRUE))
 > mydata
  P1 P2 P3 P1.P2 P1.P3 P2.P3 A B C
1  1  2  3     4     5     6 7 8 9
 > names(mydata)
[1] "P1"    "P2"    "P3"    "P1.P2"
"P1.P3" "P2.P3" "A"     "B"    
"C"
 > grep("~",names(mydata))
integer(0)
 > grep(".",names(mydata))
[1] 1 2 3 4 5 6 7 8 9

How can I check for this character ? And by the way, can anyone explain 
to me the result of the last grep call?

Thank you in advance.

Sebastien

Try 'check.names=FALSE' in the read.table call.

On Fri, Aug 22, 2008 at 6:11 PM, S?bastien <pomchip at free.fr>
wrote:
> Dear R users,
>
> I have to import some csv files in which column headers contain the
> character "~". Following the following import call, the character
seems to
> be replaced by dots in the column names of my data frame. Plus, I cannot
> query names(mydata) to find the column index which header should contain
"~"
> or "."
>
>> mydata <- data.frame(read.table("mycsv.csv", sep =
",", header = TRUE,
>> na.strings = ".", as.is = TRUE))
>> mydata
>  P1 P2 P3 P1.P2 P1.P3 P2.P3 A B C
> 1  1  2  3     4     5     6 7 8 9
>> names(mydata)
> [1] "P1"    "P2"    "P3"    "P1.P2"
"P1.P3" "P2.P3" "A"     "B"    
"C"   >
> grep("~",names(mydata))
> integer(0)
>> grep(".",names(mydata))
> [1] 1 2 3 4 5 6 7 8 9
>
> How can I check for this character ? And by the way, can anyone explain to
> me the result of the last grep call?
>
> Thank you in advance.
>
> Sebastien
>
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-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

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