Dart Lists

In this chapter, we will learn about dart lists data types and various properties and methods available within lists with the help of examples.

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Dart Lists

The lists are collections of ordered groups of objects. The lists are also known as arrays.

We can create a list data type by enclosing the values in square braces. For example,

var numbers = [4, 8, 5];

Another way to create a list is by passing the new keyword to the List object. For example,

var names = new List();
names[0] = 4; 
names[1] = 8; 
names[2] = 5;

In dart lists, all the values should have the same data type.

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Accessing List Values

The list values are also known as elements.

Each element has it’s index number which indicates the position in the list.

The element’s index starts with 0. And the last element’s index will be length-1, where length indicates the number of elements in the list.

The index number can be used to access the element from the list. For example,

void main() {
var numbers = [4, 8, 5];

print(numbers[0]);
print(numbers[1]);
print(numbers[2]);

}

Output

4
8
5

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Updating List Values

We can update the list values by accessing the index of the list and adding the new values. For example,

void main() {
var numbers = [4, 8, 5];
print(numbers);
numbers[2] = 22;
print(numbers);

}

Output

[4, 8, 5]
[4, 8, 22]

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Dart List Properties

Dart list also provides very useful properties. Some of them are:

Properties	Description
isEmpty	Returns true if the list has no elements
isNotEmpty	Returns true if the list has at least one element
length	Returns the number of elements in the list
first	Returns the first element in the list
last	Returns the last element in the list
reversed	Returns an iterable object containing the lists values in the reverse order
single	Checks if the list has only one element and returns it

Dart List Properties Examples

void main() {

var names = ["John", "Jackson", "Anna", "Amanda"];
var names1 = ["Amanda"];

print(names.isEmpty);
print(names.isNotEmpty);
print(names.length);
print(names.first);
print(names.last);

print(names.reversed);
  
print(names1.single);
}

Output

false
true
4
John
Amanda
(Amanda, Anna, Jackson, John)
Amanda

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Dart List Methods

Dart list also provides various useful methods. Some of them are:

Methods	Description
add()	Adds the specified value at the end of the list
addAll()	Adds multiple values to the given list
insert()	Adds the specified value at the specified index of the list
remove()	Removes one element at a time from the given list.
removeAt()	Removes an element from the specified index position
removeLast()	Remove the last element from the given list
removeRange()	Removes the item within the specified range

Dart List Methods Examples

void main() {
var numbers = [4, 8, 5];
print(numbers);
numbers.add(12);
print(numbers);

numbers.addAll([15, 16, 18]);
print(numbers);

numbers.insert(2, 55);
print(numbers);

numbers.remove(8);
print(numbers);

numbers.removeAt(3) ;  
print(numbers);

numbers.removeLast();
print(numbers);

numbers.removeRange(2,5);
print(numbers);

}

Output

[4, 8, 5]
[4, 8, 5, 12]
[4, 8, 5, 12, 15, 16, 18]
[4, 8, 55, 5, 12, 15, 16, 18]
[4, 55, 5, 12, 15, 16, 18]
[4, 55, 5, 15, 16, 18]
[4, 55, 5, 15, 16]
[4, 55]

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In the next chapter, we will learn about dart maps.