在R函数的参数集中操纵输入变量

Question

I am trying to solve the issue of input variable manipulation in R function. The function is as follows:

testFun<-function(x,y){
   x+y
}

I want to run in such a way:

testFun(x=1,y=5+x)

but the error is generated:

Browse[1]> testFun(x=1,y=5+x)
Error during wrapup: object 'x' not found

From the argument evaluation poin of view it is a mistake. So I need to have 'x' either a default value or outside value (details I have scanned in http://adv-r.had.co.nz/Functions.html#function-arguments ).

So my question is whether it is possible to make such a manipulation in one row, without making a wrappers or outside values?

It is supposed to have the output:

run:

testFun(x=1,y=5+x)

output:

7

Answer 1

You can use <- but it will create the variable in your global environment. See the following for example:

testFun(x <- 1, y = 5 + x)
# [1] 7