如何从Dart中的字符串中仅提取数字？

import 'package:regex/regex.dart';

void main() {
  String str = "abc123def456";
  RegExp regex = RegExp(r'\d+');
  Iterable<Match> matches = regex.allMatches(str);
  
  List<String> numbers = [];
  for (Match match in matches) {
    numbers.add(match.group(0));
  }
  
  print(numbers); // 输出: [123, 456]
}

void main() {
  String str = "abc123def456";
  
  List<String> numbers = [];
  String currentNumber = "";
  
  for (int i = 0; i < str.length; i++) {
    if (str[i].contains(RegExp(r'[0-9]'))) {
      currentNumber += str[i];
    } else if (currentNumber.isNotEmpty) {
      numbers.add(currentNumber);
      currentNumber = "";
    }
  }
  
  if (currentNumber.isNotEmpty) {
    numbers.add(currentNumber);
  }
  
  print(numbers); // 输出: [123, 456]
}