[R] String mathematical function to R-function

[Renaud Lancelot]

> fun_String <- "-100*x1 + 0*x2 + 100*x3"
>
> fun <- function(x1, x2, x3){
+   eval(parse(text = fun_String))
+   }
>
> fun(4:0, -2:2, 0:4)
[1] -400 -200    0  200  400

Best,

Renaud

2006/7/8, Cleber N.Borges <klebyn at yahoo.com.br>:
>
>
> hello
>
> I make a subroutine that give-me a (mathematical)
> function in string format.
> I would like transform this string into function ( R
> function ).
>
> thanks for any tips.
> cleber
>
>
> #e.g.
> fun_String = "-100*x1 + 0*x2 + 100*x3"
>
> fun <- function(x1,x2,x3){
> return(
> ############
>
> evaluation( fun_String )
>
> ############
> )
>
>
>
>
>
> True String mathematical function :-(  :-(
>
> > nomes
> [1] "8.49*x1*z1 + 6.13*x1*z2 + 6.4*x1*z3 + 6.9*x2*z1 +
> 4.54*x2*z2 + 3.99*x2*z3 + 19.31*x3*z1 + 12.49*x3*z2 +
> 3.86*x3*z3 + 5.25*x1*z1*z2 + -6.2*x1*z1*z3 +
> 9.07*x1*z2*z3 + 10.87*x2*z1*z2 + 9.78*x2*z1*z3 +
> 49.05*x2*z2*z3 + 4.56*x1*x2*z1 + -4.9*x1*x2*z2 +
> 4.01*x1*x2*z3 + -0.39*x3*z1*z2 + 14.34*x3*z1*z3 +
> 0.7*x3*z2*z3 + -2.84*x1*x3*z1 + 20.25*x1*x3*z2 +
> 6.44*x1*x3*z3 + -4.91*x2*x3*z1 + 5.45*x2*x3*z2 +
> 37.99*x2*x3*z3 + -22.24*x1*z1*z2*z3 +
> -97.41*x2*z1*z2*z3 + -8.67*x1*x2*z1*z2 +
> 49.14*x1*x2*z1*z3 + 14.24*x1*x2*z2*z3 +
> 282.71*x3*z1*z2*z3 + 34.83*x1*x3*z1*z2 +
> 111.2*x1*x3*z1*z3 + 101.38*x1*x3*z2*z3 +
> -6.93*x2*x3*z1*z2 + 90.16*x2*x3*z1*z3 +
> -9.11*x2*x3*z2*z3 + 17.22*x1*x2*x3*z1 +
> -29.42*x1*x2*x3*z2 + -19.87*x1*x2*x3*z3 +
> -277.41*x1*x2*z1*z2*z3 + -482.82*x1*x3*z1*z2*z3 +
> -688.23*x2*x3*z1*z2*z3 + -588.4*x1*x2*x3*z1*z2 +
> -197.31*x1*x2*x3*z1*z3 + -722.58*x1*x2*x3*z2*z3 +
> 5536.59*x1*x2*x3*z1*z2*z3"
> >
>
>
>
>
>
> _______________________________________________________
>
> o discador agora!
>
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>


-- 
Renaud LANCELOT
Département Elevage et Médecine Vétérinaire (EMVT) du CIRAD
Directeur adjoint chargé des affaires scientifiques

CIRAD, Animal Production and Veterinary Medicine Department
Deputy director for scientific affairs

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