R将文本字段转换为函数

Question

我想使用字段中的信息并将其包含在 R 函数中，例如:

data #name of the data.frame with only one raw

"(if(nclusters>0){OptmizationInputs[3,3]*beta[1]}else{0})" # this is the raw

如果我想在函数中使用这些信息，我该怎么做？

Another example:
A=c('x^2')
B=function (x) A
B(2)
"x^2"  # this is the return. I would like to have the return something like 2^2=4.

Answer 1

使用 body<-并解析

A <- 'x^2'

B <- function(x) {}

body(B) <- parse(text = A)

B(3)
## [1] 9

还有更多想法here