R help - Jul 2001 - Forcing variables types when using read.table

Perhaps I am being thick, but I can not figure out how to force read.table to
treat as character something that "looks" numeric to it. Here is a
simple example:
> version
         _                   
platform sparc-sun-solaris2.6
arch     sparc               
os       solaris2.6          
system   sparc, solaris2.6   
status                       
major    1                   
minor    3.0                 
year     2001                
month    06                  
day      22                  
language R                   
> file.show("temp.txt")
sedol,price
000312,47
071290,112
> read.table("temp.txt", header = TRUE, sep = ",")
  sedol price
1   312    47
2 71290   112
> read.table("temp.txt", header = TRUE, sep = ",", as.is
= TRUE)
  sedol price
1   312    47
2 71290   112
> 
Note that "sedol" is really a character string (it is an international
identifier for stocks) while price is numeric. How can I get read.table to
create sedol as character (and therefore keep around the leading zeroes)? I
guess that I am looking for an option like "what" from scan . . .

Thanks,

Dave Kane 
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On 11-Jul-2001 David Kane  <David Kane wrote:
> Perhaps I am being thick, but I can not figure out how to force read.table
to
> treat as character something that "looks" numeric to it. Here is
a simple
> example:
> 
>> version
>          _                   
> platform sparc-sun-solaris2.6
> arch     sparc               
> os       solaris2.6          
> system   sparc, solaris2.6   
> status                       
> major    1                   
> minor    3.0                 
> year     2001                
> month    06                  
> day      22                  
> language R                   
>> file.show("temp.txt")
> sedol,price
> 000312,47
> 071290,112
> 
>> read.table("temp.txt", header = TRUE, sep = ",")
>   sedol price
> 1   312    47
> 2 71290   112
>> read.table("temp.txt", header = TRUE, sep = ",",
as.is = TRUE)
>   sedol price
> 1   312    47
> 2 71290   112
>> 
> 
> Note that "sedol" is really a character string (it is an
international
> identifier for stocks) while price is numeric. How can I get read.table to
> create sedol as character (and therefore keep around the leading zeroes)? I
> guess that I am looking for an option like "what" from scan . . .
You can just use scan instead of read.table:

x <- scan("temp.txt", what=list("",0), skip=1, 
sep=",")
names(x) <- scan("temp.txt", what="", nlines=1,
sep=",")
as.data.frame(x)

This will convert sedol to a factor variable, which seems appropriate.

Martyn

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