How to convert data in Flutter and Dart cover image

How to convert data in Flutter and Dart

Luiz Eduardo • December 5, 2019


During development it is common to convert data from one type to another to perform the most diverse operations and Dart offers a number of methods to perform the conversions within Flutter.

Convert String to Int

var strtoint = int.parse("999");

The int.parse method parses the source as an integer literal and returns the value.

The source must be a non-empty sequence of base base digits, optionally prefixed with a minus or plus sign (‘-‘ or ‘+’). Must not be null.

If the source String does not contain a valid integer literal, optionally prefixed by a sign, a FormatException is thrown.

Convert String to double

var strtodouble = double.parse('1.1');

The double.parse() method accepts an optional sign (+ or -) followed by the characters "Infinity", "NaN" or a floating point representation.

A floating point representation is composed of a mantissa and an optional part of the exponent.

The mantissa is a decimal point (.) Followed by a sequence of digits (decimals) or a sequence of digits optionally followed by a decimal point and optionally more digits.

The exponent (optional) part consists of the character “e” or “E“, an optional sign and one or more digits. String must not be null. Leading and trailing whitespaces are ignored.

If the source String is not a valid double literal, then onError is called with the source as an argument and its return value will be used. If no onError is provided, a FormatException is thrown.

Convert int to String

Dart offers a special method called toString() to convert integer to String.

String inttostr = 1.toString ();

int.toString() returns the representation of an integer numeric literal.

Convert double to String

Dart offers a special method called toString() to convert double numbers to String.

String doubletostr = 1.9.toString();

double.toString() returns the representation of a numeric literal, so that the double value closest to the mathematical value of the representation is this double.