c# - C#自定义组对于大型数据集非常慢

当我运行以下代码（其中campaigns.Count（）为200,000）时，该代码的运行速度确实很慢。

List<Campaign> listCampaigns = new List<Campaign>();
        foreach (var item in campaigns)
        {
            if (listCampaigns.Where(a => a.CampaignName == item.CampaignName && a.Term == item.Term).Count() == 0)
            {
                //this doesn't exist
                listCampaigns.Add(item);
            }
            else
            {
                //this exists already
                var campaign = listCampaigns.Where(a => a.CampaignName == item.CampaignName && a.Term == item.Term).First();
                campaign.TotalVisits += item.TotalVisits;
                List<Conversion> listConversions = item.Conversions.ToList();
                listConversions.AddRange(campaign.Conversions.ToList());
                campaign.Conversions = listConversions.ToArray();
            }
        }

是否有必要优化此代码的一部分或使用另一种方法来加快速度？

任何建议表示赞赏。谢谢。

最佳答案

这应该快得多：

List<Campaign> listCampaigns = new List<Campaign>();
foreach (var g in campaigns.GroupBy(c => new { c.CampaignName, c.Term }))
{
    var campaign = g.First();
    campaign.TotalVisits = g.Sum(x => x.TotalVisits);
    campaign.Conversions = g.SelectMany(c => c.Conversions).ToArray();
    listCampaigns.Add(campaign);
}

关于c# - C#自定义组对于大型数据集非常慢，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/5173871/