int

Integer values no larger than 64 bits, depending on the platform.

double

64-bit (double-precision) floating-point numbers, as specified by the IEEE 754 standard.

Both int and double are subtypes of num. The num type includes basic operators such as +, -, /, and *, and is also where you’ll find abs(), ceil(), and floor(), among other methods. (Bitwise operators, such as >>, are defined in the int class.) If num and its subtypes don’t have what you’re looking for, the dart:math library might.

Strings

A Dart string (String object) holds a sequence of UTF-16 code units. You can use either single or double quotes to create a string:

var s1 = 'Single quotes work well for string literals.';
var s2 = "Double quotes work just as well.";
var s3 = 'It\'s easy to escape the string delimiter.';
var s4 = "It's even easier to use the other delimiter.";

You can put the value of an expression inside a string by using ${expression}. If the expression is an identifier, you can skip the {}. To get the string corresponding to an object, Dart calls the object’s toString() method.

Booleans

To represent boolean values, Dart has a type named bool. Only two objects have type bool: the boolean literals true and false, which are both compile-time constants. This means if you're checking if a string is empty or a number is 0 you must do so explicitly.

// Check for an empty string.
var fullName = '';
assert(fullName.isEmpty);

// Check for zero.
var hitPoints = 0;
assert(hitPoints <= 0);

// Check for null.
var unicorn;
assert(unicorn == null);

// Check for NaN.
var iMeantToDoThis = 0 / 0;
assert(iMeantToDoThis.isNaN);