[R] variable name of variable in dataframe

[Hotz, T.]

Dear Tobias,

The trick is "Programming on the Language", see e.g. the "R Language Manual". 
Construct the expression you want, and have it explicitly parsed and evaluated.

toy <- function(b=.95){
  toyframe <- eval(parse(text=paste("data.frame(lion", b, " = c(1, 2))", sep="")))
  return(toyframe)
z}
toy()
toy(0)

HTH

Thomas


---

Thomas Hotz
Research Associate in Medical Statistics
University of Leicester
United Kingdom

Department of Epidemiology and Public Health
22-28 Princess Road West
Leicester
LE1 6TP
Tel +44 116 252-5410
Fax +44 116 252-5423

Division of Medicine for the Elderly
Department of Medicine
The Glenfield Hospital
Leicester
LE3 9QP
Tel +44 116 256-3643
Fax +44 116 232-2976


> -----Original Message-----
> From: Tobias Verbeke [mailto:tobias_verbeke at skynet.be]
> Sent: 25 July 2003 11:16
> To: R-help
> Subject: [R] variable name of variable in dataframe
> 
> 
> Dear list,
> 
> If I have this toy function:
> 
> toy <- function(b=.95){
> toyframe <- data.frame(lion.95 = c(1, 2))
> return(toyframe)
> }
> 
> How can I obtain that for any value b, 
> the name of the column becomes "lionb", 
> i.e. lion.95 if b = .95, lion.85 if b = .85 etc.
> knowing that .95 (.85 etc.) may also be
> given as 0.95 (0.85 etc.) but that the
> result should be lion.95 (lion.85 etc.) 
> 
> 
> Thanks in advance,
> 
> Tobias
> 
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