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Dart Collection
Lists in Dart

List in Dart

Lists are used to store multiple items in a single variable. Lists are a type of collection in Dart. Lists can be declared in two ways. List are mutable, which means, they can be changed after they have been created. List are similar to arrays in other programming languages.

Syntax

 
List<data_type> list_name = [value1, value2, value3, ...];

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  print(names);
}

Output


[John, Doe, Smith]

List Properties

Properties are the values associated with a Dart class. A list has the following properties:

PropertyDescription
lengthReturns the length of the list
reversedReturns an iterable object containing the list values in the reverse order
isEmptyReturns true if the list is empty
isNotEmptyReturns true if the list is not empty

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  print(names.length);
  print(names.reversed);
  print(names.isEmpty);
  print(names.isNotEmpty);
}

Output


3
(Smith, Doe, John)
false
true

List Methods

Methods are the functions associated with a Dart class. A list has the following methods:

MethodDescription
add()Adds an element at the end of the list
addAll()Adds all the elements of a list to the current list
insert()Inserts an element at the given index in the list
insertAll()Inserts all the elements of a list to the current list starting from the given index
remove()Removes the first occurrence of the specified element in the list
removeAt()Removes the element at the specified index from the list
removeLast()Removes the last element from the list
removeRange()Removes all the elements in the given range from the list
removeWhere()Removes all the elements of the list that satisfy the given predicate
retainWhere()Removes all the elements of the list that fail to satisfy the given predicate
clear()Removes all the elements from the list
sort()Sorts the elements of the list in ascending order
sublist()Returns a new list containing the elements of the list from the given start index to the end index
shuffle()Randomly shuffles the elements of the list
asMap()Returns a map view of the list where keys are the indices and values are the corresponding elements
forEach()Applies the given function on each element of the list
map()Returns a new list containing the results of applying the given function on each element of the list
where()Returns a new list containing the elements of the list that satisfy the given predicate
any()Returns true if any of the elements in the list satisfy the given predicate
every()Returns true if every element in the list satisfies the given predicate
firstWhere()Returns the first element in the list that satisfies the given predicate
lastWhere()Returns the last element in the list that satisfies the given predicate
singleWhere()Returns the single element in the list that satisfies the given predicate
join()Concatenates all the elements of the list to a string
reduce()Applies the given function on each element of the list in left-to-right order and returns a single value
fold()Applies the given function on each element of the list in left-to-right order and returns a single value
indexOf()Returns the first index of the given element in the list
lastIndexOf()Returns the last index of the given element in the list
contains()Returns true if the list contains the given element
toSet()Returns a set containing the elements of the list
getRange()Returns an iterable object containing the elements of the list from the given start index to the end index
setRange()Replaces the elements in the given range in the list with the elements of the given iterable object
replaceRange()Replaces the elements in the given range in the list with the given value
fillRange()Replaces the elements in the given range in the list with the given value

Now, Lets understand each method with an example.

add() in list

The add() method is used to add an element at the end of the list.

Syntax

 
list_name.add(element);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  names.add("William");
  print(names);
}

Output


[John, Doe, Smith, William]

addAll() in list

The addAll() method is used to add all the elements of a list to the current list.

Syntax

 
list_name.addAll(list_name);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  List<String> names2 = ["William", "Henry"];
  names.addAll(names2);
  print(names);
}

Output


[John, Doe, Smith, William, Henry]

insert() in list

The insert() method is used to insert an element at the given index in the list.

Syntax

 
list_name.insert(index, element);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  names.insert(1, "William");
  print(names);
}

Output


[John, William, Doe, Smith]

insertAll() in list

The insertAll() method is used to insert all the elements of a list to the current list starting from the given index.

Syntax

 
list_name.insertAll(index, list_name);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  List<String> names2 = ["William", "Henry"];
  names.insertAll(1, names2);
  print(names);
}

Output


[John, William, Henry, Doe, Smith]

remove() in List

The remove() method is used to remove the first occurrence of the specified element in the list.

Syntax

 
list_name.remove(element);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  names.remove("Doe");
  print(names);
}

Output


[John, Smith]

removeAt() in list

The removeAt() method is used to remove the element at the specified index from the list.

Syntax

 
list_name.removeAt(index);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  names.removeAt(1);
  print(names);
}

Output


[John, Smith]

removeLast() in list

The removeLast() method is used to remove the last element from the list.

Syntax

 
list_name.removeLast();

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  names.removeLast();
  print(names);
}

Output


[John, Doe]

removeRange() in list

The removeRange() method is used to remove all the elements in the given range from the list.

Syntax

 
list_name.removeRange(start_index, end_index);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith", "William", "Henry"];
  names.removeRange(1, 3);
  print(names);
}

Output


[John, William, Henry]

removeWhere() in list

The removeWhere() method is used to remove all the elements of the list that satisfy the given predicate.

Syntax

 
list_name.removeWhere((element) => condition);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith", "William", "Henry"];
  names.removeWhere((element) => element.length < 4);
  print(names);
}

Output


[John, Smith, William, Henry]

retainWhere() in list

The retainWhere() method is used to remove all the elements of the list that fail to satisfy the given predicate.

Syntax

 
list_name.retainWhere((element) => condition);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith", "William", "Henry"];
  names.retainWhere((element) => element.length < 4);
  print(names);
}

Output


[Doe]

clear() in list

The clear() method is used to remove all the elements from the list.

Syntax

 
list_name.clear();

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith", "William", "Henry"];
  names.clear();
  print(names);
}

Output


[]

sort() in list

The sort() method is used to sort the elements of the list in ascending order.

Syntax

 
list_name.sort();

Example

 
void main() {
  List<int> numbers = [5, 2, 4, 3, 1];
  numbers.sort();
  print(numbers);
}

Output


[1, 2, 3, 4, 5]

sublist() in list

The sublist() method is used to return a new list containing the elements of the list from the given start index to the end index.

Syntax

 
list_name.sublist(start_index, end_index);

Example

 
void main() {
  List<int> numbers = [5, 2, 4, 3, 1];
  print(numbers.sublist(1, 3));
}

Output


[2, 4]

shuffle() in list

The shuffle() method is used to randomly shuffle the elements of the list.

Syntax

 
list_name.shuffle();

Example

 
void main() {
  List<int> numbers = [5, 2, 4, 3, 1];
  numbers.shuffle();
  print(numbers);
}

Output


[2, 5, 1, 3, 4]

asMap() in list

The asMap() method is used to return a map view of the list where keys are the indices and values are the corresponding elements.

Syntax

 
list_name.asMap();

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  print(names.asMap());
}

Output


{0: John, 1: Doe, 2: Smith}

forEach() in list

The forEach() method is used to apply the given function on each element of the list.

Syntax

 
list_name.forEach((element) => function);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  names.forEach((element) => print(element));
}

Output


John
Doe
Smith

map() in list

The map() method is used to return a new list containing the results of applying the given function on each element of the list.

Syntax

 
list_name.map((element) => function);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  var new_names = names.map((element) => element.toUpperCase());
  print(new_names);
}

Output


(JOHN, DOE, SMITH)

where() in list

The where() method is used to return a new list containing the elements of the list that satisfy the given predicate.

Syntax

 
list_name.where((element) => condition);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  var new_names = names.where((element) => element.length < 4);
  print(new_names);
}

Output


(John, Doe)

any()

The any() method is used to return true if any of the elements in the list satisfy the given predicate.

Syntax

 
list_name.any((element) => condition);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  var new_names = names.any((element) => element.length < 4);
  print(new_names);
}

Output


true

every() in list

The every() method is used to return true if every element in the list satisfies the given predicate.

Syntax

 
list_name.every((element) => condition);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  var new_names = names.every((element) => element.length < 4);
  print(new_names);
}

Output


false

firstWhere() in list

The firstWhere() method is used to return the first element in the list that satisfies the given predicate.

Syntax

 
list_name.firstWhere((element) => condition);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  var new_names = names.firstWhere((element) => element.length < 4);
  print(new_names);
}

Output


John

lastWhere() in list

The lastWhere() method is used to return the last element in the list that satisfies the given predicate.

Syntax

 
list_name.lastWhere((element) => condition);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  var new_names = names.lastWhere((element) => element.length < 4);
  print(new_names);
}

Output


Smith

singleWhere() in list

The singleWhere() method is used to return the single element in the list that satisfies the given predicate.

Syntax

 
list_name.singleWhere((element) => condition);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith", "William", "Henry"];
  var new_names = names.singleWhere((element) => element.length < 4);
  print(new_names);
}

Output


Doe

join() in list

The join() method is used to concatenate all the elements of the list to a string.

Syntax

 
list_name.join(separator);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith"];
  var new_names = names.join(" ");
  print(new_names);
}

Output


John Doe Smith

reduce() in list

The reduce() method is used to apply the given function on each element of the list in left-to-right order and returns a single value.

Syntax

 
list_name.reduce((value, element) => function);

Example

 
void main() {
  List<int> numbers = [5, 2, 4, 3, 1];
  var new_numbers = numbers.reduce((value, element) => value + element);
  print(new_numbers);
}

Output


15

fold() in list

The fold() method is used to apply the given function on each element of the list in left-to-right order and returns a single value.

Syntax

 
list_name.fold(initial_value, (value, element) => function);

Example

 
void main() {
  List<int> numbers = [5, 2, 4, 3, 1];
  var new_numbers = numbers.fold(0, (value, element) => value + element);
  print(new_numbers);
}

Output


15

indexOf() in list

The indexOf() method is used to return the first index of the given element in the list.

Syntax

 
list_name.indexOf(element);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith", "William", "Henry"];
  var new_names = names.indexOf("Smith");
  print(new_names);
}

Output


2

lastIndexOf() in list

The lastIndexOf() method is used to return the last index of the given element in the list.

Syntax

 
list_name.lastIndexOf(element);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith", "William", "Henry"];
  var new_names = names.lastIndexOf("Smith");
  print(new_names);
}

Output


2

contains() in list

The contains() method is used to return true if the list contains the given element.

Syntax

 
list_name.contains(element);

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith", "William", "Henry"];
  var new_names = names.contains("Smith");
  print(new_names);
}

Output


true

toSet() in list

The toSet() method is used to return a set containing the elements of the list.

Syntax

 
list_name.toSet();

Example

 
void main() {
  List<String> names = ["John", "Doe", "Smith", "William", "Henry"];
  var new_names = names.toSet();
  print(new_names);
}

Output


{John, Doe, Smith, William, Henry}

getRange() in list

The getRange() method is used to return an iterable object containing the elements of the list from the given start index to the end index.

Syntax

 
list_name.getRange(start_index, end_index);

Example

 
void main() {
  List<int> numbers = [5, 2, 4, 3, 1];
  var new_numbers = numbers.getRange(1, 3);
  print(new_numbers);
}

Output


(2, 4)

setRange() in list

The setRange() method is used to replace the elements in the given range in the list with the elements of the given iterable object.

Syntax

 
list_name.setRange(start_index, end_index, iterable_object);

Example

 
void main() {
  List<int> numbers = [5, 2, 4, 3, 1];
  numbers.setRange(1, 3, [6, 7]);
  print(numbers);
}

Output


[5, 6, 7, 3, 1]

replaceRange() in list

The replaceRange() method is used to replace the elements in the given range in the list with the given value.

Syntax

 
list_name.replaceRange(start_index, end_index, value);

Conclusion

In this tutorial, we have learnt about Lists in Dart. We have learnt about the properties and methods of Lists in Dart.

Contributing

Contributions are welcome!

Introduction to Collections in DartSets and Maps in Dart