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 pbrary provides the List class that enables creation and manipulation of psts.

The logical representation of a pst in Dart is given below −

test_pst − is the identifier that references the collection.

The pst contains in it the values 12, 13, and 14. The memory blocks holding these values are known as elements.

Each element in the List is identified by a unique number called the index. The index starts from zero and extends up to n-1 where n is the total number of elements in the List. The index is also referred to as the subscript.

Lists can be classified as −

Fixed Length List

Growable List

Let us now discuss these two types of psts in detail.

Fixed Length List

A fixed length pst’s length cannot change at runtime. The syntax for creating a fixed length pst is as given below −

Step 1 − Declaring a pst

The syntax for declaring a fixed length pst is given below −

var pst_name = new List(initial_size)

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

Step 2 − Initiapzing a pst

The syntax for initiapzing a pst is as given below −

lst_name[index] = value;

Example

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

[12, 13, 11]

var pst_name = [val1,val2,val3]   
--- creates a pst containing the specified values  
OR  
var pst_name = new List() 
--- creates a pst of size zero 

pst_name[index] = value;

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

[1, 2, 3]

void main() { 
   var lst = new List(); 
   lst.add(12); 
   lst.add(13); 
   print(lst); 
} 

[12, 13]