public/subjects/mobile-dev/data-structures

Data Structures

Instructions

Let's take a look at List, Set, and Map.

Declare and initialize following variables:

• listNum of type List<int>, containing a list of integers. There must be at least 5 elements in the list.
• listObj of type List<Object>, containing a list of objects. There must be at least 4 elements in the list.
• listStr of type List<String>, containing a list of strings. There should be at least 3 elements in the list.
• listList of type List<List<Object>>, containing a list of lists containing listNum, listObj, listStr.
• setStr of type Set<String>, containing at least 3 strings.
• mapStr of type Map<String, int> containing at least 3 pairs.

List

List is an array of elements:

var listNum = [1, 2, 3];

List<int> listNum = [1, 2, 3];

Set

Set is an unordered collection of unique items:

var set = {'Germany', 'Kazakhstan', 'France', 'England'};

Set<String> set = {'Germany', 'Kazakhstan', 'France', 'England'};

Map

Map is a key-value data structure:

var mapRadius = {
  'Earth': 6378.1,
  'Jupiter': 71492,
  'Moon': 1738.1,
};

Map<String, double> mapRadius = {
  'Earth': 6378.1,
  'Jupiter': 71492,
  'Moon': 1738.1,
};

No main is needed.