CODEWITHSUNDEEP
dart
Augustin R
Augustin R

Reputation: 7799

Dart : How to get second to last item in a List

I would like to get the second to last item in a List, similarly than with getter last.

I tried the following :

final list = [1, 2, 3, 4, 5];

final secondToLast = (list..removeLast()).last; // Mutates the List

However it mutates the List.

Upvotes: 2

Views: 5564

Answers (1)

Augustin R
Augustin R

Reputation: 7799

There is many options available (however you should make sure that list is not null and has at least 2 elements) :

final list = [1, 2, 3, 4, 5];

// Works only for Lists
final secondToLast = list[list.length - 2];
final secondToLast = list.reversed.elementAt(1);
final secondToLast = list.reversed.skip(1).first;

// Works for any Iterable
final secondToLast = list.elementAt(list.length - 2);

To get something similar to last, you can write an extension on Iterable :

extension CustomIterable<T> on Iterable<T> {
  T? get secondToLast {
    return this == null || length < 2 ? null : elementAt(length - 2);
  }
}

Upvotes: 8

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