Begginer's guide to using List in Dart/Flutter

In this post we will take a look at how to use List in Dart/Flutter with its various methods.

In Dart, a list is a collection of objects that are ordered and indexed. A list is similar to an array in other programming languages, but it has additional functionality like dynamically growing or shrinking in size as elements are added or removed. A list can contain elements of any type, including numbers, strings, and even other lists.

Here are some common operations that can be performed on Dart lists, along with examples:

1. Creating a List To create a list in Dart, you can use the List constructor, which takes an optional length argument, or you can use list literals, which are denoted by square brackets [].

   // Using the List constructor
   List<int> numbers = List(5);
   numbers[0] = 1;
   numbers[1] = 2;
   numbers[2] = 3;
   numbers[3] = 4;
   numbers[4] = 5;
   
   // Using list literals
   List<String> names = ['Alice', 'Bob', 'Charlie'];
   

2. Accessing Elements in a List Elements in a list can be accessed using their index. The first element in a list has an index of 0, the second element has an index of 1, and so on.

   List<int> numbers = [1, 2, 3, 4, 5];
   
   // Accessing an element by index
   int firstNumber = numbers[0]; // 1
   
   // Changing an element by index
   numbers[3] = 10;
   
   // Getting the length of a list
   int length = numbers.length; // 5
   

3. Adding and Removing Elements in a List Elements can be added or removed from a list using various methods.

   List<String> names = ['Alice', 'Bob', 'Charlie'];
   
   // Adding a single element to the end of the list
   names.add('David');
   
   // Adding multiple elements to the end of the list
   names.addAll(['Eve', 'Frank']);
   
   // Inserting an element at a specific index
   names.insert(1, 'Grace');
   
   // Removing an element by index
   names.removeAt(2);
   
   // Removing the last element
   names.removeLast();
   
   // Removing a specific element
   names.remove('Bob');
   
   // Removing all elements from the list
   names.clear();
   

4. Iterating Over a List There are several ways to iterate over the elements in a list.

   List<String> names = ['Alice', 'Bob', 'Charlie'];
   
   // Using a for loop
   for (int i = 0; i < names.length; i++) {
     print(names[i]);
   }
   
   // Using a for-in loop
   for (String name in names) {
     print(name);
   }
   
   // Using a forEach() method
   names.forEach((name) => print(name));
   

5. Sorting a List A list can be sorted using the sort() method.

   List<int> numbers = [3, 1, 4, 2, 5];
   
   // Sorting the list in ascending order
   numbers.sort();
   
   // Sorting the list in descending order
   numbers.sort((a, b) => b.compareTo(a));
   

Dart lists provide a flexible way to work with collections of data. They can be used to store any type of object, and there are many built-in methods for adding, removing, and iterating over elements in a list.

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