How to create a Map with Initial Key-Value Pairs in Dart

How to create a Map with Initial Key-Value Pairs in Dart ?

Answer

To create a map with initial key-value pairs in Dart, you can use the map literal syntax. This creates a new map object with predefined key-value pairs.

✐ Examples

1 Creating a Map with Initial Key-Value Pairs

We can create a map in Dart with initial key-value pairs using the map literal syntax, which initializes a map with predefined key-value pairs.

For example,

We start by declaring a variable named myMap. This variable will hold our map with initial key-value pairs.
We use the map literal syntax to create a new map object. In Dart, the map literal syntax allows us to specify key-value pairs directly within curly braces.
The newly created map is now assigned to the myMap variable. In this example, the map has string keys and integer values.
We can now perform various operations on this map, such as adding more key-value pairs, checking for the presence of keys, and retrieving values.

Dart Program

void main() {
    // Declare a map with initial key-value pairs
    Map<String, int> myMap = {
        'one': 1,
        'two': 2,
        'three': 3
    };

    // Operations on the map
    myMap.forEach((key, value) {
        print('$key: $value');
    });
}

Output

one: 1
two: 2
three: 3

2 Creating a Map with Different Key-Value Types

We can create a map in Dart with initial key-value pairs of different types using the map literal syntax.

For example,

We start by declaring a variable named studentGrades. This variable will hold our map with initial key-value pairs where keys are strings (student names) and values are characters (grades).
We use the map literal syntax to create a new map object. In Dart, the map literal syntax allows us to specify key-value pairs directly within curly braces.
The newly created map is now assigned to the studentGrades variable. In this example, the map has string keys and string values representing grades.
We can now perform various operations on this map, such as adding more key-value pairs, checking for the presence of keys, and retrieving values.

Dart Program

void main() {
    // Declare a map with initial key-value pairs
    Map<String, String> studentGrades = {
        'Alice': 'A',
        'Bob': 'B',
        'Charlie': 'C'
    };

    // Operations on the map
    studentGrades.forEach((key, value) {
        print('$key: $value');
    });
}

Output

Alice: A
Bob: B
Charlie: C

3 Creating a Map with Integer Keys and Double Values

We can create a map in Dart with initial key-value pairs where keys are integers and values are doubles using the map literal syntax.

For example,

We start by declaring a variable named productPrices. This variable will hold our map with initial key-value pairs where keys are integers (product IDs) and values are doubles (prices).
We use the map literal syntax to create a new map object. In Dart, the map literal syntax allows us to specify key-value pairs directly within curly braces.
The newly created map is now assigned to the productPrices variable. In this example, the map has integer keys and double values.
We can now perform various operations on this map, such as adding more key-value pairs, checking for the presence of keys, and retrieving values.

Dart Program

void main() {
    // Declare a map with initial key-value pairs
    Map<int, double> productPrices = {
        101: 29.99,
        102: 39.99,
        103: 49.99
    };

    // Operations on the map
    productPrices.forEach((key, value) {
        print('Product $key: $value');
    });
}

Output

Product 101: 29.99
Product 102: 39.99
Product 103: 49.99

Summary

In this tutorial, we learned How to create a Map with Initial Key-Value Pairs in Dart language with well detailed examples.

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