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rfor-loopformula

R apply a formula in a for loop

I would like to create a function in which a mathematical formula is set as argument (with only two possible variables) and use this formula within two nested loop. The idea is to be able to change the formula as I would like to create y values based on the formula. This is what I have done but I cannot apply the formula:

foo <- function(formula = y~a-b){
formula = as.formula(y ~a -b)
formula = formula[[3:length(formula)]]
result = NULL
for (a in 1:30) {
 for(b in 1:30){
  result = c(result, noquote(formula))
 }
}
return(result)
}
Solution

  • Create a template fun and then insert the formula into its body.

    foo <- function(formula = y ~ a - b) {
  fun <- function(a, b) {}
  body(fun) <- formula[[length(formula)]]
  result <- NULL
  for (a in 1:30) {
    for(b in 1:30) {
      result = c(result, fun(a, b))
    }
  }
  return(result)
}

# test
result <- foo()