[R] How to interpret the name of an object literally?

[Duncan Murdoch]

On 11/24/2009 1:13 PM, novocaine wrote:
> Hi, 
> 
> I can't seem to figure out how to tell R to stop expanding an object. I
> would like to use the literal name rather than the expanded value. 
> 
> The issue occurs in a function I've been writing. The problematic part looks
> like this: 
> 
> # "fund" is a matrix of open, high, low, close, and volume prices
> returns <- function(fund)
> {
>      p_12ago = as.vector(fund[nrow(fund)-252,6])
>      perc_diff_12mo = ((p_last - p_12ago) / p_last)*100
> 
> #This is the line that's giving me problems:
>      funds=c(as.character(fund))
> 
>      mo12=c(perc_diff_12mo)
>      final_results=data.frame(funds,mo12)
>      return(final_results)
> }
> 
> I can't figure out how to insert the original argument from the function (in
> this case the name of the fund). 
> 
> Ultimately I want to be able to do returns("GOOG"), and have the output in
> this format:
> 
> funds     12mo
> GOOG     14%
> 
> I've tried using as.character(), quote(), dQuote(), sQuote(), gsub(), cat(),
> and a bunch of combinations of them. I'm brand new to R, so I apologize if
> I'm going about this in the wrong way. 
> 
> Thanks in advance for any help!

Use deparse(substitute(fund)).  The inner function gives you the 
expression passed as fund, the deparse() turns it into a string.

You can in weird cases get more than one line of output from deparse; 
you could use the width.cutoff and/or nlines arguments to control this.

Duncan Murdoch