Say there is a list of numbers. What is the difference between adding
add(int index, Object x)
and setting an object to the list
set(int index, Object x).
Don't they essentially do the same thing? Aren't both functions just adding the
Object x
to the specified index?
Set override your value at index position, add extends your values in array(old values remains) and put new value into index position.
From the documentation http://docs.oracle.com/javase/7/docs/api/java/util/List.html
add(int index, E element) Inserts the specified element at the specified position in this list (optional operation).
set(int index, E element) Replaces the element at the specified position in this list with the specified element (optional operation).
So no. They don't do the same thing. add adds. set replaces an existing element.
If there is no element a the index, set will return an error:
IndexOutOfBoundsException - if the index is out of range (index < 0 || index >= size())
You could, therefore, try them both:
try
{
list.set(index, obj);
}
catch(IndexOutOfBoundsException ex)
{
list.add(index, obj);
}
Try to set, and if it returns that specific error, add instead.
