Dart – Data Types

Like other languages (C, C++, Java), whenever a variable is created, each variable has an associated data type. In Dart language, there is the type of values that can be represented and manipulated in a programming language. The data type classification is as given below: 

Data Type	Keyword	Description
Number	int, double, num, BigInt	Numbers in Dart are used to represent numeric literals
Strings	String	Strings represent a sequence of characters
Booleans	bool	It represents Boolean values true and false
Lists	List	It is an ordered group of objects
Maps	Map	It represents a set of values as key-value pairs

1. Number: The number in Dart Programming is the data type that is used to hold the numeric value. Dart numbers can be classified as: 

• The int data type is used to represent whole numbers.
• The double data type is used to represent 64-bit floating-point numbers.
• The num type is an inherited data type of the int and double types.

Dart

void main() {

   // declare an integer
   int num1 = 2;

   // declare a double value
   double num2 = 1.5;

   // print the values
   print(num1);
   print(num2);
   var a1 = num.parse("1");
   var b1 = num.parse("2.34");

   var c1 = a1+b1;
   print("Product = ${c1}");
}

Output:

2
1.5
Product = 3.34

2. String: It used to represent a sequence of characters. It is a sequence of UTF-16 code units. The keyword string is used to represent string literals. String values are embedded in either single or double-quotes.

Dart

void main() {

    String string = 'Geeks''for''Geeks';
    String str = 'Coding is ';
    String str1 = 'Fun';
    print (string);
    print (str + str1);
}

Output:

GeeksforGeeks
Coding is Fun

3. Boolean: It represents Boolean values true and false. The keyword bool is used to represent a Boolean literal in DART. 

Dart

void main() {
  String str = 'Coding is ';
  String str1 = 'Fun';

  bool val = (str==str1);
  print (val);
}

Output:

false

4. List: List data type is similar to arrays in other programming languages. A list is used to represent a collection of objects. It is an ordered group of objects. 

Dart

void main()
{
    List gfg = new List(3);
    gfg[0] = 'Geeks';
    gfg[1] = 'For';
    gfg[2] = 'Geeks';

    print(gfg);
    print(gfg[0]);
}

Output:

[Geeks, For, Geeks]
Geeks

5. Map: The Map object is a key and value pair. Keys and values on a map may be of any type. It is a dynamic collection.

Dart

void main() {
  Map gfg = new Map();
  gfg['First'] = 'Geeks';
  gfg['Second'] = 'For';
  gfg['Third'] = 'Geeks';
  print(gfg);
}

Output:

{First: Geeks, Second: For, Third: Geeks}

Note: If the type of a variable is not specified, the variable’s type is dynamic. The dynamic keyword is used as a type annotation explicitly.