indexWhere method

  1. @override
int indexWhere(
  1. Predicate<T> test, [
  2. int start = 0
])
override

The first index in the list that satisfies the provided test.

Searches the list from index start to the end of the list. The first time an object o is encountered so that test(o) is true, the index of o is returned.

final notes = <String>['do', 're', 'mi', 're'];
final first = notes.indexWhere((note) => note.startsWith('r')); // 1
final second = notes.indexWhere((note) => note.startsWith('r'), 2); // 3

Returns -1 if element is not found.

final notes = <String>['do', 're', 'mi', 're'];
final index = notes.indexWhere((note) => note.startsWith('k')); // -1

Implementation

@override
int indexWhere(Predicate<T> test, [int start = 0]) {
  final index = list.lastIndexWhere(test, start == 0 ? null : start);
  return (index == -1) ? -1 : list.length - index - 1;
}