How to Remove a Key-Value Pair from a Map in Dart - Step by Step Examples

How to Remove a Key-Value Pair from a Map in Dart ?

Answer

To remove a key-value pair from a map in Dart, you can use the remove method. This method allows you to remove the key-value pair associated with the specified key.

✐ Examples

1 Removing a Key-Value Pair Using remove Method

We can remove a key-value pair from a map in Dart using the remove method, which removes the key-value pair associated with the specified key.

For example,

We start by declaring and initializing a map named myMap with some key-value pairs. In this example, the map has string keys and integer values.
We use the remove method to remove the key-value pair associated with the key 'two'. The remove method removes the key-value pair from the map and returns the value associated with the removed key.
We print the contents of the map to the console using the print function to verify that the key-value pair has been removed.

Dart Program

void main() {
    // Declare and initialize a map
    Map<String, int> myMap = {
        'one': 1,
        'two': 2,
        'three': 3
    };

    // Remove a key-value pair using remove method
    myMap.remove('two');

    // Print the contents of the map
    print(myMap);
}

Output

{one: 1, three: 3}

2 Handling Key Not Found Using remove Method

We can handle the case where a key is not found in a map in Dart using the remove method, which returns null if the key is not present.

For example,

We start by declaring and initializing a map named myMap with some key-value pairs. In this example, the map has string keys and integer values.
We use the remove method to attempt to remove the key-value pair associated with the key 'four'. The remove method returns null if the key is not found.
We print the contents of the map to the console using the print function to verify that the map is unchanged.

Dart Program

void main() {
    // Declare and initialize a map
    Map<String, int> myMap = {
        'one': 1,
        'two': 2,
        'three': 3
    };

    // Attempt to remove a non-existent key-value pair using remove method
    myMap.remove('four');

    // Print the contents of the map
    print(myMap);
}

Output

{one: 1, two: 2, three: 3}

3 Removing Multiple Key-Value Pairs Using remove Method

We can remove multiple key-value pairs from a map in Dart using the remove method, which removes the key-value pairs associated with the specified keys.

For example,

We start by declaring and initializing a map named myMap with some key-value pairs. In this example, the map has string keys and integer values.
We use the remove method to remove the key-value pairs associated with the keys 'one' and 'three'. The remove method removes the key-value pairs from the map and returns the value associated with the removed keys.
We print the contents of the map to the console using the print function to verify that the key-value pairs have been removed.

Dart Program

void main() {
    // Declare and initialize a map
    Map<String, int> myMap = {
        'one': 1,
        'two': 2,
        'three': 3
    };

    // Remove multiple key-value pairs using remove method
    myMap.remove('one');
    myMap.remove('three');

    // Print the contents of the map
    print(myMap);
}

Output

{two: 2}

Summary

In this tutorial, we learned How to Remove a Key-Value Pair from a Map in Dart language with well detailed examples.

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How to Remove a Key-Value Pair from a Map in Dart - Step by Step Examples