Python 2D list (grid)

Code pattern

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Definition

A list of lists addressed as grid[row][column]; loop with nested for loops.

Example

grid[1][2] = 5

Found in: syllabus, course specifications, 2025 HSC marking guidelines, school notes, past SDD papers.

Where you'll use it in the test

Syllabus area: Code patterns.

Question types it can appear in

Python: Grid (2025 Q26, sample Q21)
Code reading: Code or algorithm reading: interpret a fragment and state its output or purpose.

Where it has appeared in the paper

The Software Engineering Project (Part A, B). Part letters follow each paper’s own layout.

How to use it

A model sentence

General advice, built from the definition and example above

Code pattern: “A list of lists addressed as grid[row][column]; loop with nested for loops.” Then apply it: grid[1][2] = 5

In a short answer, give the definition in your own words first, then tie it to the situation in the question. Do not copy the example above unless it fits the scenario.

Command words used with it

From the linked past questions

Identify: Recognise and name. (Sample exam Q21a (1 mark): 2D arrays (Python))

Official worked answer

Sample exam Q21a (1 mark): 2D arrays (Python) (1 mark): official criteria and sample answer

Criteria

1: Identifies the correct answer.

Sample answer

Timetable[0][2] (day index 0 = Monday, period index 2 = Period 3).

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Go deeper

Flashcard: Python 2D list (grid) in Code Patterns: Pseudocode, Python, SQL, CSS (Years 11 and 12) · study that set
Memorise: Python basics: input, selection, loops, strings
Full term page: every question, note and marking comment for Python 2D list (grid)

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