[R] Using as.formula() with the reshape package cast

[Gavin Simpson]

On Tue, 2009-04-07 at 09:47 -0400, ryan.sheftel at malbecpartners.com
wrote:
> I am trying to use the "cast" function from the reshape package, where the 
> formula is not passed in directly, but as the result of the as.formula() 
> function. 
> 
> Using reshape v. 0.7.2 
> 
> I am able to properly melt() by data with: 
> 
> > molten <- melt(x, id=1:2) 
> 
> then I can properly cast with this: 
> 
> > cast(molten, days ~ variable) 
> 
> but if I try 
> 
> > cast(molten, as.function("days ~ variable")) 
                    ^^^^^^^^^

Did you really use as.function not as.formula as you claim or is this a
typo in composing this posting? If this is what you typed, that may well
be the source of the error.

HTH

G

> 
> if returns the error: 
> 
> Error in check_formula(formula, varnames) : 
>         Formula contains variables not in list of known variables 
> 
> I am not sure if the problem is with cast or as.formula() 
> 
> I did confirm that: 
> 
> > x <- days ~ variable 
> 
> > y <- as.formula("days ~ variable") 
> 
> > x==y 
> TRUE
> 
> 
> 	[[alternative HTML version deleted]]
> 
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