How to capitalize the first letter of a string in dart?

Since dart version 2.6, dart supports extensions:

extension StringExtension on String {    String capitalize() {      return "${this[0].toUpperCase()}${this.substring(1)}";    }}

So you can just call your extension like this:

import "string_extension.dart";var someCapitalizedString = "someString".capitalize();

Copy this somewhere:

extension CapExtension on String {  String get inCaps => this.length > 0 ?'${this[0].toUpperCase()}${this.substring(1)}':'';  String get allInCaps => this.toUpperCase();  String get capitalizeFirstofEach => this.replaceAll(RegExp(' +'), ' ').split(" ").map((str) => str.inCaps).join(" ");}

Usage:

final helloWorld = 'hello world'.inCaps; // 'Hello world'final helloWorld = 'hello world'.allInCaps; // 'HELLO WORLD'final helloWorldCap = 'hello world'.capitalizeFirstofEach; // 'Hello World'

Old answer:

main() {  String s = 'this is a string';  print('${s[0].toUpperCase()}${s.substring(1)}');}

Substring parsing in the other answers do not account for locale variances.The toBeginningOfSentenceCase() function in the intl/intl.dart package handles basic sentence-casing and the dotted "i" in Turkish and Azeri.

import 'package:intl/intl.dart';...String sentence = toBeginningOfSentenceCase('this is a string'); // This is a string