Question

I have a function which requests numeric input from the user as follows:

request_KBEHAVIOR<-function()
{
as.numeric(readline("Please enter Kramer's behavior>>> "))
}

So Kramer’s behavior is a value between 0 and 1 (a probability), and a user would enter in something like “.5”

However, I’d also like the user to input an equation like =1/exp(runif(1)). Is this possible?

For instance in excel, you can type a value into a cell, or you can type a function like =1/exp(rand()) and you can reference that cell in any other equation. Thank you so much for your help in advance.

Answer 1

You can use eval(parse(text=...)):

request_KBEHAVIOR<-function() as.numeric(eval(parse(text=
                                 readline("Please enter Kramer's behavior>>> "))))

request_KBEHAVIOR()
Please enter Kramer's behavior>>> 1/exp(runif(1))
# [1] 0.379733

request_KBEHAVIOR()
Please enter Kramer's behavior>>> 0.5
# [1] 0.5