Lists, Maps, and Sets in Flutter - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a List in Flutter?

A List is an ordered collection of items. You can add, remove, or access items by their position (index). Think of it like a shopping list where order matters.

beginner

How does a Map work in Flutter?

A Map stores data as key-value pairs. Each key is unique and points to a value. It's like a dictionary where you look up a word (key) to find its meaning (value).

beginner

What is a Set in Flutter and when to use it?

A Set is a collection of unique items with no order. Use it when you want to store items but avoid duplicates, like a guest list where each name appears once.

beginner

How do you add an item to a List in Flutter?

Use the add() method. For example: myList.add('apple'); This adds 'apple' to the end of the list.

intermediate

How to check if a Map contains a key in Flutter?

Use the containsKey() method. For example: myMap.containsKey('name') returns true if 'name' is a key in the map.

Which Flutter collection type stores items in a specific order and allows duplicates?

A None of the above

B List

C Set

D Map

Lists keep items in order and allow duplicates.

What does a Map in Flutter use to access its values?

A Key

B Index

C Position

D Value

Maps use keys to access their values.

Which collection type automatically prevents duplicate items?

A List

B Map

C Set

D Array

Sets only store unique items.

How do you add a new key-value pair to a Map in Flutter?

A myMap['key'] = 'value'

B myMap.add('key', 'value')

C myMap.insert('key', 'value')

D myMap.push('key', 'value')

Use myMap['key'] = 'value' to add or update entries.

Which method checks if a List contains a specific item?

A exists()

B has()

C find()

D contains()

The contains() method checks for an item in a List.

Explain the differences between Lists, Maps, and Sets in Flutter.

Think about how you store and access data in each collection.

Describe a real-life example where you would use a Set instead of a List.

Consider situations where repeating items cause problems.