Dart's Collection: Maps
Explore how Dart Maps store unique keys and their associated values for efficient data lookup. Learn to create typed maps, handle null-safe access when keys are missing, and manipulate entries using built-in methods. This lesson helps you master Maps as a core Dart collection essential for managing state and organizing data in your applications.
We'll cover the following...
We have seen how Lists use numerical indices and Sets enforce uniqueness. A Map is an unordered collection of key-value pairs. We use a Map when we want to look up a specific value using a unique identifier known as a key. Every key in a Map must be unique, but multiple keys can point to identical values.
Creating a map
We create a map using curly braces {}. To ensure type safety, we use typed literals by specifying both the key type and the value type inside angle brackets <KeyType, ValueType> just before the braces.
The complete syntax for creating a map looks like this:
final mapName = <KeyType, ValueType>{key1: value1, key2: value2};
While we can create an empty map using a constructor like Map(), modern Dart strongly prefers typed literals because they clearly define the expected data types and reduce boilerplate.
If we assign a ...