Question

我要根据某些逻辑执行一些收集和返回排名我希望优化这个工作代码，因为我认为它可以更好（可能使用任务？）

这是执行搜索的代码和扩展方法

public class Counterpart
{
    public int Id { get; set; }

    public string Code { get; set; }

    public string Description { get; set; }

    public IEnumerable<Alias> Aliases { get; set; }

    public override bool Equals(object obj)
    {
        Counterpart obj2 = obj as Counterpart;
        if (obj2 == null) return false;
        return Id == obj2.Id;
    }
}

public class Alias
{
    public int? Type { get; set; }

    public string Description { get; set; }
}

internal class CounterPartRanking
{
    public int Rank { get; set; }

    public Counterpart CounterPart { get; set; }
}

public static class CounterpartExtensions
{
    public static IEnumerable<Counterpart> SearchWithRank(this IEnumerable<Counterpart> source, string pattern)
    {
        var items1 = source.Where(x => x.Code == pattern);
        var items2 = source.Where(x => x.Code.StartsWith(pattern));
        var items3 = source.Where(x => x.Code.Contains(pattern));
        var items4 = source.Where(x => x.Description.Contains(pattern));
        var items5 = source.Where(x => x.Aliases != null && x.Aliases.Any(y => y.Description == pattern));
        var items6 = source.Where(x => x.Aliases != null && x.Aliases.Any(y => y.Description.StartsWith(pattern)));
        var items7 = source.Where(x => x.Aliases != null && x.Aliases.Any(y => y.Description.Contains(pattern)));

        Stopwatch sw = Stopwatch.StartNew();
        var rankedItems = new List<CounterPartRanking>();


        if (items1.Any())
            rankedItems.AddRange(items1.Select(x => new CounterPartRanking { Rank = 1, CounterPart = x }));
        if (items2.Any())
            rankedItems.AddRange(items2.Select(x => new CounterPartRanking { Rank = 2, CounterPart = x }));
        if (items3.Any())
            rankedItems.AddRange(items3.Select(x => new CounterPartRanking { Rank = 3, CounterPart = x }));
        if (items4.Any())
            rankedItems.AddRange(items4.Select(x => new CounterPartRanking { Rank = 4, CounterPart = x }));
        if (items5.Any())
            rankedItems.AddRange(items5.Select(x => new CounterPartRanking { Rank = 5, CounterPart = x }));
        if (items6.Any())
            rankedItems.AddRange(items6.Select(x => new CounterPartRanking { Rank = 6, CounterPart = x }));
        if (items7.Any())
            rankedItems.AddRange(items7.Select(x => new CounterPartRanking { Rank = 7, CounterPart = x }));

        sw.Stop();

        Debug.WriteLine("Time elapsed {0} for {1}", sw.Elapsed, pattern);
        var items = rankedItems.OrderBy(x => x.Rank).Select(x => x.CounterPart);
        var distinct = items.Distinct();

        return distinct;
    }
}

有什么建议吗？感谢

Answer 1

利用Contains(pattern)，StartsWith(pattern)和== pattern越来越具体的子集这一事实会有所帮助：

即。

var items3 = source.Where(x => x.Code.Contains(pattern));
var items2 = items3.Where(x => x.Code.StartsWith(pattern));
var items1 = items2.Where(x => x.Code == pattern);

应该导致比每次检查source整个

更少的比较

Answer 2

看看这是否提高了性能

   public static class CounterpartExtensions
    {
        public static IEnumerable<Counterpart> SearchWithRank(this IEnumerable<Counterpart> source, string pattern)
        {
            Stopwatch sw = Stopwatch.StartNew();
            var rankedItems = new List<CounterPartRanking>();

            foreach (Counterpart counterpart in source)
            {
                if ((counterpart.Code != null) && (counterpart.Code == pattern))
                {
                    rankedItems.AddRange(new CounterPartRanking { Rank = 1, CounterPart = counterpart });
                }
                else
                {
                    if ((counterpart.Code != null) && (counterpart.Code.StartsWith(pattern)))
                    {
                        rankedItems.AddRange(new CounterPartRanking { Rank = 2, CounterPart = counterpart });
                    }
                    else
                    {
                        if ((counterpart.Code != null) && (counterpart.Code.Contains(pattern) == pattern))
                        {
                            rankedItems.AddRange(new CounterPartRanking { Rank = 3, CounterPart = counterpart });
                        }
                    }
                }
               if ((counterpart.Description != null) && (counterpart.Description.Contains(pattern) == pattern))
                {
                    rankedItems.AddRange(new CounterPartRanking { Rank = 4, CounterPart = counterpart });
                }
               if ((counterpart.Aliases != null) && (counterpart.Aliases == pattern))
               {
                   rankedItems.AddRange(new CounterPartRanking { Rank = 5, CounterPart = counterpart });
               }
               else
               {
                   if ((counterpart.Aliases != null) && (counterpart.Aliases.StartsWith(pattern)))
                   {
                       rankedItems.AddRange(new CounterPartRanking { Rank = 6, CounterPart = counterpart });
                   }
                   else
                   {
                       if ((counterpart.Aliases != null) && (counterpart.Aliases.Contains(pattern)))
                       {
                           rankedItems.AddRange(new CounterPartRanking { Rank = 7, CounterPart = counterpart });
                       }
                   }
               }
            }


            sw.Stop();

            Debug.WriteLine("Time elapsed {0} for {1}", sw.Elapsed, pattern);
            var items = rankedItems.OrderBy(x => x.Rank).Select(x => x.CounterPart);
            var distinct = items.Distinct();

            return distinct;
        }
    }

Answer 3

我喜欢这种方法：

public static IEnumerable<Counterpart> SearchWithRank(this IEnumerable<Counterpart> source, string pattern)
{
    var sources = new []
    {
        source.Where(x => x.Code == pattern),
        source.Where(x => x.Code.StartsWith(pattern)),
        source.Where(x => x.Code.Contains(pattern)),
        source.Where(x => x.Description.Contains(pattern)),
        source.Where(x => x.Aliases != null && x.Aliases.Any(y => y.Description == pattern)),
        source.Where(x => x.Aliases != null && x.Aliases.Any(y => y.Description.StartsWith(pattern))),
        source.Where(x => x.Aliases != null && x.Aliases.Any(y => y.Description.Contains(pattern))),
    };

    Stopwatch sw = Stopwatch.StartNew();

    var rankedItems =
        sources
            .SelectMany((x, n) => x.Select(y => new CounterPartRanking { Rank = n + 1, CounterPart = y }))
            .ToList();

    sw.Stop();

    Debug.WriteLine("Time elapsed {0} for {1}", sw.Elapsed, pattern);
    var items = rankedItems.OrderBy(x => x.Rank).Select(x => x.CounterPart);
    var distinct = items.Distinct();

    return distinct;
}

它可能不会更快，但它更简洁的代码。在我的书中，这种方式更好。

使用排名优化集合中的搜索

3 个答案: