Can a function argument call an element in a list/dataframe?-CodePudding

I am pretty new to R and this is probably an easy question so sorry about that! Let me present a simple case to make sure my question clearer

Let's say I create a list

testlist = list(a = 1:3, b = 4:6, c= 7:9)
print(testlist)
$a
[1] 1 2 3

$b
[1] 4 5 6

$c
[1] 7 8 9

I want to create a function where you input either a, b, or c and it returns the values associated with the selected element. What I tried was this

testfunc = function(element){
  d = testlist$element
  return(d)
}

No matter what you put as the element, the function returns NULL. How should I change the function such that whatever is inputted in (element) is put after the $?

CodePudding user response：

We can use [[ instead of $

testfunc = function(element){
  d = testlist[[element]]
  return(d)
}

-testing

> testfunc("a")
[1] 1 2 3