Dart Programming - Lists

A very commonly used collection in programming is an array. Dart represents arrays in the form of List objects. A List is simply an ordered group of objects. The dart:core library provides the List class that enables creation and manipulation of lists

Lists can be of 

  • Fixed Length List
  • Growable List

Fixed Length List

A fixed length list’s length cannot change at runtime

 Declaring a list

Syntax

var list_name = new List(initial_size)

 

The above syntax creates a list of the specified size. The list cannot grow or shrink at runtime. Any attempt to resize the list will result in an exception

Initializing a list

Syntax

lst_name[index] = value;

 

Example

void main() { 
   var lst = new List(3); 
   lst[0] = 12; 
   lst[1] = 13; 
   lst[2] = 11; 
   print(lst); 
}

 

Output

[12, 13, 11]

 

Growable List

A growable list’s length can change at run-time

Example

void main() { 
   var num_list = [1,2,3]; 
   print(num_list); 
}

Output

[1, 2, 3]

 

The following example creates a zero-length list using the empty List() constructor. The add() function in the List class is used to dynamically add elements to the list

void main() { 
   var lst = new List(); 
   lst.add(1); 
   lst.add(2); 
   print(lst); 
} 

 

Output

[1,2] 

 

List Properties

The following table lists some commonly used properties of the List class in the dart:core library.

Sr.No Methods & Description
1 first

Returns the first element case.

2 isEmpty

Returns true if the collection has no elements.

3 isNotEmpty

Returns true if the collection has at least one element.

4 length

Returns the size of the list.

5 last

Returns the last element in the list.

6 reversed

Returns an iterable object containing the lists values in the reverse order.

7 single

Checks if the list has only one element and returns it.