Unit 04

Data Collections

Build four things that each hold thousands of values at once — a dataset you parse, a photograph you edit pixel by pixel, a playable 2048 and a sorting bench — and learn the arrays, ArrayLists, 2D arrays and algorithms underneath all four.

30–40% of the AP Exam~50–52 CED periods~25–29 blocks here17 topics

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What's in this unit · 47 min read

What you will build
4.1 · Privacy, bias, and data quality
4.2 · Working with Data Sets
4.3 · Creating and Indexing Arrays
4.4 · Array traversals
4.5 · Standard Array Algorithms
4.6 · Reading Text Files
4.7 · Wrapper classes
4.8 · ArrayList methods
4.9 · ArrayList traversals
4.10 · Standard ArrayList Algorithms
Project 4-A · DataLab
4.11 · Creating and Indexing 2D Arrays
4.12 · 2D array traversals
4.13 · Standard 2D Array Algorithms
Project 4-B · PicLab
Project 4-C · 2048
4.14 · Searching algorithms
4.15 · Sorting algorithms
Project 4-D · Sort
4.16 · Recursion
4.17 · Recursive Algorithms on Collections

65 quick checksannotated specimenvideoArrayList sandboxloop tracercall stack viewer+3 more

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Sources

College Board — AP Computer Science A Course and Exam Description, Effective Fall 2025