Chapter 10: ArrayLists

Sections:

10.1 ArrayLists

10.2 Comparable interface

10.3 Case study: Vocabulary comparison

Section 10.1: ArrayLists

10.1 Definitions

Definitions:

Generic class
Wrapper class
Boxing
Unboxing

10.1 Materials

Introduce ArrayList object the way you would introduce the Python list

List: basic data type, very important
Difference between list and array - memory allocation and element insertion
Dynamic arrays

Array notation

Wrapper class, everything is an object, treat primitive types as objects

What kind of things would you want to do with an ArrayList?

Basic basic operations:

Get size

Other basic operations:

Get item at index i
Set item at index i
Add item, add item at index i
Remove item
Modify item at index i

Now that we have defined these basic operations, we can move on to examples/algorithms/implementations.

Section 10.2: Comparable interface

10.2 Definitions

Definitions:

Comparison function
Natural ordering

10.2 Materials

First, need to mention unboxing: ArrayList<Integer> vs ArrayList<int>

Unboxing is a really stupid side effect of Java's implementation
Everything is an object. Except the primitive types. But everything is an object.

Comparison of objects

extend idea behind o1.equals(o2) to comparisons
lt/lte/gt/gte
how to redefine comparison operator for our own objects

Section 10.3: Vocabulary comparison

10.3 Material

Some efficiency considerations

Version 1: compute vocabulary

Add unique words to ArrayList, and sort

Version 2: compute overlap

Number of matches between two sentences

Version 3: complete program

so far, build vocab list for 2 files, compute overlap between them
now, to deal with large files, print statistics (Nwords, Noverlapwords, Percent overlap)

Chapter 10 Summary

Deliverables

ArrayList

Notation, how to use it
Conceptualizing problems that can be easily resolved with ArrayList
Adding/removing and looping over ArrayLists
Wrapper classes

Comparable

Natural ordering and compareTo() function
Implementing the Comparable interface

Case study: Vocab comparison

Count number of unique words
Count overlap between two lists
Compute statistics

Chapter 10 Homework

HW Questions

(Recommended) Self-check problems:

(Required) Exercises:

(Required) Projects:

HW Details

Self-check:

Exercises:

Projects:

Chapter 10 Code

Lecture Code

NEED TO DO ALL OF THIS

Worksheet Code