List in Dart

Lists can be useful for:

Storing data about a list of things, such as a shopping list, a to-do list, or a contact list;
Storing data about a sequence of events, such as a history list or a list of steps that need to be taken to complete a task.

Syntax

Let's look at the scheme of creating a List:


dart
List<elements_type> list_name = [element_1, element_2];

List: command to create a list;
<elements_type>: the data type for values will be stored in the middle of the list;
list_name: list name;
[element_1, element_2]: commas (,) separate the list elements.

Example

Example of creating a List with int values:

main

List<int> numbers = [1, 2, 3, 4, 5];


              1
            
List<int> numbers = [1, 2, 3, 4, 5];

List of integer numbers;
<int> type elements from List.

Adding Items

Let's add a value to the already existing list of numbers.

main

void main() {

List<int> numbers = [111, 22, 32];

print(numbers); // Output [111, 22, 32]

numbers.add(6); // Adding an item to a list

print(numbers); // Output [111, 22, 32, 6]

}


              123456
            
void main() {
  List<int> numbers = [111, 22, 32];
  print(numbers); // Output [111, 22, 32]
  numbers.add(6); // Adding an item to a list
  print(numbers); // Output [111, 22, 32, 6]
}


dart
numbers.add(6);

Let's break down the new command in detail:

numbers: list name;
add(): command that adds elements to a list;
6: the value we want to add to the list.

Deleting Items


dart
list_name.remove(element)

Let's break down the new command in detail:

numbers: list name;
remove(): command that removes the first occurrence of the specified item in the list;
element: the value we want to add to the list.

main

void main() {

List<int> numbers = [11, 22, 23];

print(numbers); // [11, 22, 23]

numbers.remove(22);

print(numbers); // [11, 23]

}


              123456
            
void main() {
  List<int> numbers = [11, 22, 23];
  print(numbers); // [11, 22, 23]
  numbers.remove(22);
  print(numbers); // [11, 23]
}

We removed 22 from the List

We heva a List:


dart
List<bool> items = [true, false];

Tudo estava claro?

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Seção 2. Capítulo 6

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