Dart int

Summary: In this tutorial, you’ll learn about the Dart int type and how to use it effectively.

Introduction to the Dart int type #

To represent integers like -1, 0, 1, 2, etc., you use the int type. In native platforms, the int type corresponds to a signed 64-bit integer.

Since Dart is also compiled to JavaScript, the int type maps to a 64-bit double-precision floating-point value on the web. This is because JavaScript only has floating-point numbers.

The following example declares a counter variable with the type int:

void main() {
  int counter = 1;
  print('counter: $counter');
}Code language: Dart (dart)

Output:

counter: 1Code language: Dart (dart)

Converting a string into an integer #

To convert a string into an integer, you use the int.parse(). For example:

void main() {
  int qty = 5;
  String amount = "100";
  int total = qty * int.parse(amount);

  print('Total: $total');
}Code language: Dart (dart)

This example declares the amount variable as a string and converts it into an integer.

The int.parse() will raise an exception if it cannot convert the string into an integer. For example:

void main() {
  String amountStr = "a100";
  int amount = int.parse(amountStr);

  print('Total: $amount');
}Code language: Dart (dart)

Error:

FormatException: Invalid radix-10 number (at character 1)
a100
^Code language: Dart (dart)

Summary #

• Use int type to represent integers.
• Use int.parse() to convert a string to an integer.