double_linked_list 1.0.2

A Generic Double Linked List data structure. This data structure allows constant time inserting at elements at both ends, and with access to any node, also allows constant time inserting new elements [...]

Double Linked List

A library presenting a generic double linked list.

Since this library uses non nullability, it will be usable with Dart 2.10 :(

Double linked list structure:

[dll_structure]

Usage

Create a new empty list, from iterables or from another list

import 'package:double_linked_list/double_linked_list.dart';

main() {
  final emptyList = DoubleLinkedList<int>.empty();
  
  final fromList = DoubleLinkedList<int>.fromIterable([1, 2, 3]);
  final fromListExtension = [1, 2, 3].toDoubleLinkedList();
  
  final fromSet = DoubleLinkedList<int>.fromIterable({1, 2, 3});
  final fromSetExtension = {1, 2, 3}.toDoubleLinkedList();
  
  final copyList = DoubleLinkedList<int>.from(fromList);
  final copyListMethod = copyList.copy();
}

Iterate over a list in normal or reverse order

import 'package:double_linked_list/double_linked_list.dart';

main() {
  final list = [1, 3, 5].toDoubleLinkedList();
  for (var node = list.first; !node.isEnd; node = node.next) {
    node = node.insertAfter(node.content + 1);
  }
  print(list); // [1, 2, 3, 4, 5, 6]
  
  for (var node = list.last; !node.isBegin; node = node.previous) {
    print(node.content);
  }
  // 6 5 4 3 2 1
}

Be careful when iterating and inserting elements:

import 'package:double_linked_list/double_linked_list.dart';

main() {
  final list = [1, 3, 5].toDoubleLinkedList();
  for (var node = list.first; !node.isEnd; node = node.next) {
    node.insertAfter(node.content + 1);
  }
}

⚠️Program stuck at an endless loop.

To avoid this, move to the inserted node:

import 'package:double_linked_list/double_linked_list.dart';

main() {
  final list = [1, 3, 5].toDoubleLinkedList();
  for (var node = list.first; !node.isEnd; node = node.next) {
    node = node.insertAfter(node.content + 1);
  }
}

You can also use most of the functions available for Iterables, and some others:

import 'package:double_linked_list/double_linked_list.dart';

main() {
  final list = [1, 2, 3].toDoubleLinkedList();

  list.forEach(print);

  list.apply((e) => e * e);
  print(list); // [1 | 4 | 9]
    
  print(list.where((e) => e.isOdd)); // [1 | 9]
    
  print(list.reduce((value, element) => value + element)); // 14
  print(list.fold<int>(-14, (value, element) => value + element)); // 0
    
  print(list.any((e) => e > 2)); // true
  print(list.every((e) => e > 2)); // false
    
  print(list.firstWhere((e) => e > 2)); // (4)
  print(list.lastWhere((e) => e > 2)); // (9)
  
}

Complete example at example.

Features and bugs

Please file feature requests and bugs at the issue tracker.