AP®︎ Computer Science A Unit 4: Notes & Study Guide
Prepare for your quiz, test, or the AP exam with a comprehensive review on Unit 4 of AP Computer Science A – Data Collections.
Unit 4: Data Collections
This unit covers working with collections of data using arrays, ArrayLists, and 2D arrays, along with common algorithms for traversal, searching, and sorting.
Begin with Topic 4.1: Ethical and Social Issues...To review Unit 4, go through each of the 17 topics below.
Everything you actually need to know for your Unit 4 test, pulled directly from the AP® Computer Science A curriculum.
Ethical and Social Issues Around Data Collection
Ethical and Social Issues Around Data Collection
- Privacy Risks in Data Collection and Storage
- Data Quality and Why It Matters
- Algorithmic Bias
Introduction to Using Data Sets
Introduction to Using Data Sets
- What a Data Set Is
- Sequential Processing One Value at a Time
- Representing Data with Tables and Diagrams
Array Creation and Access
Array Creation and Access
- What a 1D Array Is
- Declaring and Creating Arrays
- Accessing and Modifying Elements
Array Traversals
Array Traversals
- What Array Traversal Is
- The Three Ways to Traverse an Array
- Enhanced For Loop with Object References
Implementing Array Algorithms
Implementing Array Algorithms
- What Array Algorithms Are
- Standard Traversal Patterns You Must Know
- Modifying These for Context
Using Text Files
Using Text Files
- What Text Files Are and Why They Matter
- Setting Up File Input Correctly
- Scanner Methods You Must Know
Wrapper Classes
Wrapper Classes
- What Wrapper Classes Are
- Autoboxing and Unboxing
- Integer and Double Methods You Must Know
ArrayList Methods
ArrayList Methods
- What an ArrayList Is
- The Core ArrayList Methods You Must Know
- How ArrayList Operations Affect Indices
ArrayList Traversals
ArrayList Traversals
- What Traversing an ArrayList Is
- The Two Ways to Traverse
- Modifying an ArrayList During Traversal
Implementing ArrayList Algorithms
Implementing ArrayList Algorithms
- What ArrayList Algorithms Are
- Standard ArrayList Algorithm Patterns
- Traversing Multiple Lists Simultaneously
2D Array Creation and Access
2D Array Creation and Access
- What a 2D Array Is
- Creating and Initializing 2D Arrays
- Accessing Elements and Row-Major Order
2D Array Traversals
2D Array Traversals
- What 2D Array Traversal Is
- The Three Main Traversal Orders
- Enhanced For Loops with 2D Arrays
Implementing 2D Array Algorithms
Implementing 2D Array Algorithms
- What 2D Array Algorithms Are
- Standard 2D Traversal Algorithms
- Writing Original 2D Algorithms
Searching Algorithms
Searching Algorithms
- What Linear Search Is
- The Linear Search Pattern in Code
- Linear Search in 2D Arrays
Sorting Algorithms
Sorting Algorithms
- What Sorting Algorithms Do
- Selection Sort
- Insertion Sort
Recursion
Recursion
- What Recursion Is
- The Call Stack and Local Variables
- How to Trace Recursive Methods
Recursive Searching and Sorting
Recursive Searching and Sorting
- Recursive Searching and Sorting as Divide and Conquer
- Binary Search
- Merge Sort
Notes
1 credit used · 5/5 remaining