Remove from array

main.dart

/*
 * Remove from array
 * https://gist.github.com/PlugFox/8eed2788e7e6427d76db68800a1539af
 * https://dartpad.dev/8eed2788e7e6427d76db68800a1539af
 * Matiunin Mikhail <plugfox@gmail.com>, 08 May 2023
 */

import 'dart:math' show Random;

import 'package:benchmark_harness/benchmark_harness.dart';

final $random = Random();
final $arr = List<int>.generate(10000, (_) => $random.nextInt(1000));

void main() {
  $arr;
  RemoveEvenBenchmark$Reverse().report();
  RemoveEvenBenchmark$Swap().report();
}

class RemoveEvenBenchmark$Reverse extends BenchmarkBase {
  RemoveEvenBenchmark$Reverse() : super(r'RemoveEvenBenchmark$Reverse');

  @override
  void run() {
    final arr = $arr.toList();
    for (var i = arr.length - 1; i >= 0; i--) {
      if (arr[i] % 2 == 0) arr.removeAt(i);
    }
    assert(arr.every((e) => e % 2 != 0));
  }
}

class RemoveEvenBenchmark$Swap extends BenchmarkBase {
  RemoveEvenBenchmark$Swap() : super(r'RemoveEvenBenchmark$Swap');

  @override
  void run() {
    final arr = $arr.toList();
    var j = 0;
    for (var i = 0; i < arr.length; i++) {
      if (arr[i] % 2 == 0) continue;
      if (i != j) arr[j] = arr[i];
      j++;
    }
    arr.length = j;
    assert(arr.every((e) => e % 2 != 0));
  }
}