Essential Guide to Dart Data Types

print('Explicit Initialization');
  int expAge = 25;
  double expPi = 3.1415;
  print("my age is: $expAge");
  print("pi value is: $expPi");
  print("---------------------");
  print('Implicit Initialization');
  var impAge = 25;
  var impPi = 3.1415;
  print("my age is: $impAge");
  print("pi value is: $impPi");

  // in Dart:
  print('Explicit');
  String name = "xia afridi";
  print("my name is: $name");
  print('Implicit');
  var name1 = 'xia afridi';
  print("my name1 is: $name1");
  // in Flutter:
  Text("my name is: $name");

  print('Explicit');
  bool flag = false;
  String name = "xia afridi";
  var checkName = flag == false ? "null" : "$name";
  print("my name is: $checkName");

  print('implicit initialization');
  var intList = List<int>.empty(growable: true);
  intList.add(1);
  intList.addAll([2, 3, 4]);
  print(intList);
  print('-------------------------');
  print("explicit initialization");
  List<dynamic> randomList = ["xia", 12, false, 2.33];
  for (var r in randomList) {
    print(r);
  }

  print('Implicit Initialization');
  var personalData = {}; // Type: Map<dynamic, dynamic>
  personalData.addEntries({
    'name': 'xia',
    'age': 25,
    'isGraduated': true,
    'cgpa': 3.023,
  }.entries);
  print(personalData);
  print('-----------------------');
  print('Explicit Initialization');
  Map<int, String> fruits = {
    1: 'orange',
    2: 'banana',
    3: 'apple',
    4: 'fine apple',
    5: 'kiwi',
  };
  final fruitsEntriesFrom =
      Map<int, String>.from(fruits); //copy version of original or
  //Creates a Map with the same keys and values as [fruits].
  print(fruitsEntriesFrom);

  // decalare set using literal:
  Set<String> sports = {
    'cricket',
    'hockey',
    'footbal',
    'table tennis',
    'volley ball'
  };
  print(sports);
  print('----------------------');
  // declares using constructor:
  final count = Set<int>.from({1, 2, 3, 4, 5, 6, 7, 8, 9, 10});
  print(count);

// record is compex data type in dart which can stores different data with multiple typed, params and returns.
  (String, String, {int a, bool b}) record =
      ('first', a: 2, b: true, 'last'); //contains both name and unnamed params
  print(record.$1); // print single one record
  print(record.a);
  print('------');
  print(record); // print whole record
  print('------');

  print('recode runtimetype: ${record.runtimeType}'); // type check
  print('------');

  ({int number, String name}) randRecord; // named typed record
  randRecord =
      (number: 10, name: 'Record Data'); // store values as named param.
  print('named parameters record: $randRecord');
  print('------');

  // swaping integers with record data type using swap function
  (int, int) swap((int, int) record) {
    var (a, b) = record; // before swap values
    print('before swap');
    print(record);
    print('after swap');
    return (b, a); // after swap values
  }

  print('swap two ints with record using swap function');
  print(swap((4, 8)));

 String heart = '\u2665'; // heart unicode for emoji
  print('heart: $heart'); // heart emoji prints
  print('--------');
  // when runes convert to list its type changes from Runes to List<int>.
  List<int> heartRuneList = heart.runes.toList();
  print('heart runes list: $heartRuneList');
  print('--------');
  //Dart uses UTF-16 for String encoding internally. However, when you access a String's runes property,
  //Dart automatically handles any surrogate pairs behind the scenes.
  String directHit = '\u2665'; // This emoji requires a surrogate pair in UTF-16
  if (directHit.isEmpty) {
    print('emoji string is null');
  } else {
    int getSarrogatePair =
        directHit.runes.first; // equivalent to this.elementAt(0)
    print(
        'sarrogate: $getSarrogatePair'); // Prints the complete Unicode code point for the emoji
  }
  print('--------');
  // convert to string chars
  String runesToString =
      String.fromCharCodes(heart.runes); //heart.runes converts the string
  // to an iterable of its Unicode code points.
  print('runes to String: $runesToString');

 print('before changes');
  dynamic dynamicValue = "orange";
  print("fruit is: $dynamicValue");
  print('--------------------');
  print('after changes');
  dynamicValue = 30;
  print("number is: $dynamicValue");

  // declares litterals
  Symbol symbol = #hi_symble;
  print(symbol);
  print('--------');

  // declares using constructor
  var mySymble = Symbol('this_is_my_symble');
  print('${mySymble.runtimeType} $mySymble');
  //
  print('--------');

  // here for for eqwuality i pick one word from both symble vars using contains function.
  if (mySymble.toString().contains('symble') ==
      symbol.toString().contains('symble')) {
    print("symble is matched !");
  } else {
    print("symble is not matched !");
  }
  print('--------');
  // used compareT+o function for comparing and for equality i used replaceAll function applied to one of the symble.
  int symbCompareTo = mySymble.toString().compareTo(
      symbol.toString().replaceAll(symbol.toString(), mySymble.toString()));
  print(symbCompareTo);