structs-arraylist-set.md

#Setting values in an ArrayList Setting a value in an ArrayList performs an overwrite: it combines an addition and removal.

For example:

ArrayList<String> myList = new ArrayList<String>();
myList.add("Hello");
myList.add("Goodbye");
myList.add("Hi");

produces an ArrayList called myList that looks like ["Hello", "Goodbye", "Hi"]. Now, lets set "Hiya" in index 1:

myList.set(1, "Hiya");

Now, myList looks like ["Hello", "Hiya", "Hi"] – the "Hiya" string was inserted into the second position (index 1), overwriting the "Goodbye" that was there.