How to delete duplicates in a dart List? list.distinct()?

Question

How do i delete duplicates from a list without fooling around with a set? Is there something like list.distinct()? or list.unique()?

void main() {
  print(\"         


        

Answer 1

As for me one of best practices is sort array, then deduplicate it. Idea is stolen from low level languages. So,

first make sort by your own, then deduplicate equal values that are going after each other.

// easy example
void dedup(List list, {removeLast: true}) {
  int shift = removeLast ? 1 : 0;
  T compareItem;
  for (int i = list.length - 1; i >= 0; i--) {
    if (compareItem == (compareItem = list[i])) {
      list.removeAt(i + shift);
    }
  }
}

// harder example
void dedupBy(List list, I Function(T) compare, {removeLast: true}) {
  int shift = removeLast ? 1 : 0;
  I compareItem;
  for (int i = list.length - 1; i >= 0; i--) {
    if (compareItem == (compareItem = compare(list[i]))) {
      list.removeAt(i + shift);
    }
  }
}


void main() {
  List> list = [[1], [1], [2, 1], [2, 2]];
  print('$list');
  dedupBy(list, (innerList) => innerList[0]);
  print('$list');

  print('\n removeLast: false');

  List> list2 = [[1], [1], [2, 1], [2, 2]];
  print('$list2');
  dedupBy(list2, (innerList) => innerList[0], removeLast: false);
  print('$list2');
}

Output:

[[1], [1], [2, 1], [2, 2]]
[[1], [2, 1]]

removeLast: false
[[1], [1], [2, 1], [2, 2]]
[[1], [2, 2]]