[R] make elements of a list into functions

[Uwe Ligges]

On 25.03.2015 00:38, Kruti Pandya wrote:
> Hi I have a list called g as follows and I want to  make elements of g into
> functions so that I can evaluate them at randomly generated data point say
> c(0,0,0). For example,
>
> change  g[[1]]  (!x[2] & !x[3]) | (!x[2] & x[3]) | (x[2] & x[3]) to
> function(x) (!x[2] & !x[3]) | (!x[2] & x[3]) | (x[2] & x[3])
>
> change g[[2]]  (!x[2] & !x[1]) | (!x[2] & x[1]) | (x[2] & !x[1]) to
> function(x) (!x[2] & !x[1]) | (!x[2] & x[1]) | (x[2] & !x[1])
>
> and so on......
>
> So that I  can evaluate g[[1]] as follows g1<-function(x) (!x[2] & !x[3]) |
> (!x[2] & x[3]) | (x[2] & x[3])

One way:

f <- function(x) x
gfunc <- lapply(g, function(i) {body(f) <- parse(text=i); f})

So now you have functions in your list gfunc and can call them via

gfunc[[1]](c(0,0,0))


Best,
Uwe Ligges




>
>> g1(c(0,0,0))
> [1] TRUE
>
> g<-list(structure("(!x[2] & !x[3]) | (!x[2] & x[3]) | (x[2] & x[3])", class
> = "noquote"),
>          structure("(!x[2] & !x[1]) | (!x[2] & x[1]) | (x[2] & !x[1])",
> class = "noquote"),
>          structure("(!x[2] & x[3]) | (x[2] & !x[3])", class = "noquote"))
>
> g
> [[1]]
> [1] (!x[2] & !x[3]) | (!x[2] & x[3]) | (x[2] & x[3])
>
> [[2]]
> [1] (!x[2] & !x[1]) | (!x[2] & x[1]) | (x[2] & !x[1])
>
> [[3]]
> [1] (!x[2] & x[3]) | (x[2] & !x[3])
>
> Do not know how proceed. Any help is appreciated. I have created a small
> example for demo. My actual list g has 50 elements so need a function which
> can pick each element of g and convert it into function (x)......
>
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>
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