CSIS 110 - Lecture 12
Announcements
Quiz – Friday, Oct 7
Any homework questions?
Last time: Collections
We continued looking at the ArrayList class, and began looking at the remove method.
So, say that we had these ArrayLists:
private ArrayList<String> notes;
private ArrayList<Student> studentBody;
private ArrayList<Book> library;
notes = new ArrayList<String>();
studentBody = new ArrayList<Student>();
library = new ArrayList<Book>();
Assuming that these lists have items in them, how would we remove the first item from
our notebook? The 4th student from the student body? Or the last Book from the Library?
Weíve seen how to add and access items in collections - what about removing items?
ArrayList provides a remove method: remove the item at a given index from the array.
Again, index must be in the range 0 through listSize - 1.
So, to remove the first note, we would do this:
notes.remove( 0 );
How would we remove the second note in our notebook? How about the last note in the
notebook?
[Draw a notebook ArrayList with four notes, and then ask what happens after we call
remove(1) ]
Discuss how the indices of the elements change after we do a remove.
Look at notebook-j5-Brian project – it has a remove method. Show how the numbers in
the list change.
