Lesson 9 / 25

Arrays and collections

Understand Arrays and collections as a useful part of Swift.

The essential idea

Arrays and collections gives you one practical part of Swift. Start by naming the input, the change, and the expected result. This mental model matters before any syntax rule.

Place this on the learning path

A complete program moves from an idea to source code and a checked result. This topic is one step in that path.

A learning path for Swift from source to output.
Figure 4.1 — Keep the complete path visible.

Avoid this trap

Do not memorize Arrays and collections in isolation. Change one value in a small example and use feedback to correct your understanding.

Quick check

Quick check: What is a good first practice for Arrays and collections?

  • Run one small focused example.
  • Memorize without testing.
  • Ignore feedback.
Answer

Run one small focused example. — Small experiments reveal cause and effect.