function changes arrays which it shouldnt

I was trying to create a function to edit an array, and came across this annoying problem.
If you have a function which gets given an array as an input, and inside the function you set two other arrays to be that input, and then change one array in a loop, all three arrays will be changed. Below is an example of this, executed in the maxscript listener.

fn testFunction input =
(
 tempArray1 = input
 tempArray2 = input
  --this is here to stop "!REG3XP1!>" appearing(it gets added to the post unless I have something here) and messing up the rest of the code
 for i = 1 to input.count do
 (
  tempArray2[i] = 0
 )
 return #(tempArray1, tempArray2)
)
testFunction()
 
testArray = #(1, 2, 3, 4, 5, 6, 7, 8, 9)
#(1, 2, 3, 4, 5, 6, 7, 8, 9)
 
newTestArray = testFunction testArray
#(#(0, 0, 0, 0, 0, 0, 0, 0, 0), #(0, 0, 0, 0, 0, 0, 0, 0, 0))
 
newTestArray[1]
#(0, 0, 0, 0, 0, 0, 0, 0, 0)
 
newTestArray[2]
#(0, 0, 0, 0, 0, 0, 0, 0, 0)

testArray
#(0, 0, 0, 0, 0, 0, 0, 0, 0)

As you can see, it changes all three of the arrays to have nothing but 0, which it shouldn't.
I can see no reason for this behaviour, but it's quite probable I have missed something which is causing it to work like this, if not does anyone know why this happens and any way to avoid it?