How to deep Copy a List in Dart - Step by Step Examples

How to deep Copy a List in Dart ?

Answer

To deep copy a list in Dart, you can use the `map` method to iterate through the list and create a new list with cloned elements.

✐ Examples

1 Deep Copy a List of Integers

In this example,

We create a list named originalList with integer values.
We use the map method of originalList to iterate through each element and create a new list with the same elements.
The toList method converts the iterable result of map back to a list.
Finally, we print both lists to verify the deep copy.

Dart Program

void main() {
    List<int> originalList = [1, 2, 3, 4, 5];
    List<int> deepCopiedList = originalList.map((element) => element).toList();
    print('Original List: \$originalList');
    print('Deep Copied List: \$deepCopiedList');
}

Output

Original List: [1, 2, 3, 4, 5]
Deep Copied List: [1, 2, 3, 4, 5]

2 Deep Copy a List of Custom Objects

In this example,

We define a class named Person with properties name and age.
We create a list named originalList containing Person objects.
We use the map method to iterate through each Person object and create a new Person object with the same properties.
The toList method converts the iterable result of map back to a list.
Finally, we print both lists to verify the deep copy.

Dart Program

class Person {
    String name;
    int age;
    Person(this.name, this.age);
    Person clone() => Person(this.name, this.age);
    @override
    String toString() => 'Person(name: \$name, age: \$age)';
}

void main() {
    List<Person> originalList = [
        Person('Alice', 30),
        Person('Bob', 25),
        Person('Charlie', 35)
    ];
    List<Person> deepCopiedList = originalList.map((person) => person.clone()).toList();
    print('Original List: \$originalList');
    print('Deep Copied List: \$deepCopiedList');
}

Output

Original List: [Person(name: Alice, age: 30), Person(name: Bob, age: 25), Person(name: Charlie, age: 35)]
Deep Copied List: [Person(name: Alice, age: 30), Person(name: Bob, age: 25), Person(name: Charlie, age: 35)]

Summary

In this tutorial, we learned How to deep Copy a List in Dart language with well detailed examples.

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