R help - Jul 2004 - help with as.function

HI, sorry but i don't understand how to make a function with as.function()

formula<-"2+3*x"
 formu<-as.symbol(formula)
> formu
2+3*x
 formul<-as.function(alist(x=,formu))
curve(formul,1,5,col="blue")
Error in xy.coords(x, y, xlabel, ylabel, log) :
        x and y lengths differ
> typeof(formul)
[1] "closure"

and not plot the curve function, Why? Thanks Ruben

solares at unsl.edu.ar wrote:
> HI, sorry but i don't understand how to make a function with
as.function()
> 
> formula<-"2+3*x"
>  formu<-as.symbol(formula)
> 
>>formu
> 
> 2+3*x
>  formul<-as.function(alist(x=,formu))
> curve(formul,1,5,col="blue")
> Error in xy.coords(x, y, xlabel, ylabel, log) :
>         x and y lengths differ
> 
>>typeof(formul)
> 
> [1] "closure"
> 
> and not plot the curve function, Why? Thanks Ruben
> 
Hi Ruben,
How about this?

ftext <- "2 + 3 * x"
f <- as.function(alist(x=, eval(parse(text = ftext))))

or as a one-liner:

f <- as.function(alist(x=, eval(parse(text = "2 + 3 * x"))))

--sundar

<solares <at> unsl.edu.ar> writes:
> 
> HI, sorry but i don't understand how to make a function with
as.function()
> 
> formula<-"2+3*x"
>  formu<-as.symbol(formula)
> > formu
> 2+3*x
>  formul<-as.function(alist(x=,formu))
> curve(formul,1,5,col="blue")
> Error in xy.coords(x, y, xlabel, ylabel, log) :
>         x and y lengths differ
> > typeof(formul)
> [1] "closure"
> 
> and not plot the curve function, Why? Thanks Ruben
Here are two ways to create a function out of strings although
neither uses as.function:

f <- function(x){}
body(f) <- parse(text="2+3*x")

f <- eval(parse(text=paste("function(x)","2+3*x")))