[R] RE: using underscore character in column names

[Terry Westley]

Thanks to Profs Ripley and Lumley for suggesting data$"pos_x"
and to Prof Lumley for suggesting I use data$pos.x instead.

After reviewing my application, I've decided that changing
to data$pos.x in place of using data$"pos_x" is not too much
of a hardship.  

Thanks for the help.

--
Terry J. Westley, Software Systems Engineering Supervisor
Veridian Engineering, Calspan Operations
P.O. Box 400, Buffalo, NY 14225
twestley at buffalo.veridian.com    http://www.veridian.com

> -----Original Message-----
> From: Terry Westley [mailto:twestley at buffalo.veridian.com]
> Sent: Monday, August 30, 1999 1:09 PM
> To: R-Help
> Subject: using underscore character in column names
> 
> 
> Suppose you're reading data from a file in which the
> column names contain underscore characters.  Example:
> 
> ------ start of file -----
> pos_x   pos_y
>   1.0     0.0
>   2.0     1.0
> ------ end of file -------
> 
> Using read.table, I can read this file just fine:
> 
> > data <- read.table (file="data", head=T)
> > data
>   pos_x pos_y
> 1     1     0
> 2     2     1
> > 
> 
> However, I can't refer to pox_x because the _ character
> is an alternative to <- (assignment):
> 
> > data$pos_x
> Error: Object "x" not found
> 
> I could use data[1], but I'd prefer to use the column
> name.  Must I change all my column names to remove the
> underscore character or is there way to force R to
> recogize the whole column name?
> 
> Something like data${pos_x} or data$pos\_x  ???
> 
> --
> Terry J. Westley, Software Systems Engineering Supervisor
> Veridian Engineering, Calspan Operations
> P.O. Box 400, Buffalo, NY 14225
> twestley at buffalo.veridian.com    http://www.veridian.com
> 
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