kirkdrichardson · October 12, 2019 23:23
diff --git a/main.dart b/main.dart
 // Basic Data Structures in Dart (as of v2.5)

 // See live at https://dartpad.dartlang.org/a4dd3a27e5750a029de689391ae90004

 void main() {
  
 print('------------------FIXED LENGTH LIST------------------------');
  
  List<int> l = List(3);
  print(l.length);
  print(l);
  
 //   Careful! - Most methods (e.g. everything below) are for dyanmic lists only
 //   l.add(13);
 //   l.clear();
 //   l.removeLast();
 //   l.addAll([1,2,3]);
  
  // Add, update, and delete by using the index
  for (int i = 0; i < l.length; i++) l[i] = (i+1)*(i+1);
  print(l);
  print('Value of 4 is at index ${l.indexOf(4)}');
  
  
  print('\n------------------DYNAMIC LIST------------------------');
  
  // Just omit a length argument to the List constructor to create a dynamic list.
  List<int> dl = List();
  print(dl.length);
  print(dl);
  
 //   Careful - the array index can be used to update/delete, but not to add, unless that memory space exists, e.g.
 //   dl[0] = 42; // Expect error
  dl.add(43);
  dl[0] = 42; // This doesn not throw an error bc now our list is big enough.
  dl.add(43);
  dl.add(44);
  print(dl);
 
  // Many more methods are available with a dynamic list
  dl.removeLast();
  dl.addAll([99, 100, 101]);
  print(dl);
  
  
  print('\n------------------SET------------------------');
  
  // Since this is a HashMap based implementation, there are no indices.
  // This way the Set interface can check for duplicates before adding in constant rather than linear time.
  Set<int> s = Set();
  s.add(1);
  s.add(2);
  bool added = s.add(3);
  print('Unique value was added: $added');
  s.add(3);
  print(s);
  
  added = s.add(3);
  print('Non-unique value was added: $added');
  
  print('');
  Set<String> s2 = Set.from(['Hello', 'Privet', 'Hola']); // Nice static method
  
  if (!s2.isEmpty && !s2.contains('Gamarjoba')) s2.add('Gamarjoba');
  bool removed = s2.remove('Hello');
  print('Item was successfully removed: $removed');
  s2.forEach((String greeting) => print("$greeting! 👋")); // Iterable
  s2.clear();
  print(s2);
  
  
  
  print('\n------------------MAP------------------------');
  
  Map<String, int> grades = Map();
  grades['A'] = 5;
  grades['B'] = 7;
  grades['C'] = 3;
  grades['D'] = 1;
  grades['F'] = 2;
  
  int totalStudents = grades.values.reduce((int total, int cnt) => total + cnt);
  Set<String> possibleGrades = grades.keys.toSet();
  
  print('There are $totalStudents students in the class');
  print('There are ${possibleGrades.length} possible grades');
  
  int failingStudentCount = grades['D'] + grades['F'];
  
  print("""
  Passing student count: ${totalStudents - failingStudentCount}
  Failing student count: $failingStudentCount
  """);
  
  // Can also create a map using a literal
  Map<String, int> ages = {
    'Suzy': 21,
    'Ahmed': 24,
    'Drake': 20
  };
  
  ages.addAll({'Tara': 23, 'Tristan': 22});
  print(ages);
 }
	// Basic Data Structures in Dart (as of v2.5)

	// See live at https://dartpad.dartlang.org/a4dd3a27e5750a029de689391ae90004

	void main() {

	print('------------------FIXED LENGTH LIST------------------------');

	List<int> l = List(3);
	print(l.length);
	print(l);

	// Careful! - Most methods (e.g. everything below) are for dyanmic lists only
	// l.add(13);
	// l.clear();
	// l.removeLast();
	// l.addAll([1,2,3]);

	// Add, update, and delete by using the index
	for (int i = 0; i < l.length; i++) l[i] = (i+1)*(i+1);
	print(l);
	print('Value of 4 is at index ${l.indexOf(4)}');


	print('\n------------------DYNAMIC LIST------------------------');

	// Just omit a length argument to the List constructor to create a dynamic list.
	List<int> dl = List();
	print(dl.length);
	print(dl);

	// Careful - the array index can be used to update/delete, but not to add, unless that memory space exists, e.g.
	// dl[0] = 42; // Expect error
	dl.add(43);
	dl[0] = 42; // This doesn not throw an error bc now our list is big enough.
	dl.add(43);
	dl.add(44);
	print(dl);

	// Many more methods are available with a dynamic list
	dl.removeLast();
	dl.addAll([99, 100, 101]);
	print(dl);


	print('\n------------------SET------------------------');

	// Since this is a HashMap based implementation, there are no indices.
	// This way the Set interface can check for duplicates before adding in constant rather than linear time.
	Set<int> s = Set();
	s.add(1);
	s.add(2);
	bool added = s.add(3);
	print('Unique value was added: $added');
	s.add(3);
	print(s);

	added = s.add(3);
	print('Non-unique value was added: $added');

	print('');
	Set<String> s2 = Set.from(['Hello', 'Privet', 'Hola']); // Nice static method

	if (!s2.isEmpty && !s2.contains('Gamarjoba')) s2.add('Gamarjoba');
	bool removed = s2.remove('Hello');
	print('Item was successfully removed: $removed');
	s2.forEach((String greeting) => print("$greeting! 👋")); // Iterable
	s2.clear();
	print(s2);



	print('\n------------------MAP------------------------');

	Map<String, int> grades = Map();
	grades['A'] = 5;
	grades['B'] = 7;
	grades['C'] = 3;
	grades['D'] = 1;
	grades['F'] = 2;

	int totalStudents = grades.values.reduce((int total, int cnt) => total + cnt);
	Set<String> possibleGrades = grades.keys.toSet();

	print('There are $totalStudents students in the class');
	print('There are ${possibleGrades.length} possible grades');

	int failingStudentCount = grades['D'] + grades['F'];

	print("""
	Passing student count: ${totalStudents - failingStudentCount}
	Failing student count: $failingStudentCount
	""");

	// Can also create a map using a literal
	Map<String, int> ages = {
	'Suzy': 21,
	'Ahmed': 24,
	'Drake': 20
	};

	ages.addAll({'Tara': 23, 'Tristan': 22});
	print(ages);
	}