Skip to main content
HT
HerbDev Application Rescue
← Learning hub

Vocabulary

Understand the term. Connect the concept.

A practical dictionary of 512 AI, machine learning, mathematics, and programming terms from HerbDev’s AI Vocabulary app. Start with a definition, explore an example, then follow the concepts behind it.

Linked concepts open in a new tab. Audio reads the definition and example.

Pure Function

Functions & Programming Concepts · Level 2 of 5

Pure Function

A function whose result depends only on its inputs and that has no observable side effects.

Purity makes reasoning and testing easier but does not imply computational simplicity.

Example

A routine returns the sum of its arguments without changing external state.

Listen to the definition and example

Audio transcript

Pure Function. A function whose result depends only on its inputs and that has no observable side effects. Purity makes reasoning and testing easier but does not imply computational simplicity. For example: A routine returns the sum of its arguments without changing external state.

Explore this concept

A useful analogy

A calculator that always gives the same result for the same inputs and leaves the room unchanged.

Why it matters

This helps you distinguish a computation’s contract, inputs, outputs, and behavior.

Technical detail

Referential transparency allows replacing a call by its value without changing observable program behavior.

Common misconception

Returning a value does not make a function pure if it also mutates external state.

Start with

Related concepts

Quick recall question

Try answering before looking back at the definition.

Put the terminology into context: How AI works · Machine-native representations · All learning paths

Manage browser learning data

“Remove my test data” clears all AI 101 and ML 101 scores, reviews, project checklists and rating selections, plus saved vocabulary and recent history in this browser. Test entries cannot be separated from other learning progress. Cookie preferences, security protections, submitted feedback, contact emails and past analytics are kept.