c# - 嵌套循环的代码效率 c#

Question

这是我使用嵌套循环的函数，例如:

public string HGSearchNew(HolidayFeedService.PackageHolidays.SearchCriteria objsearchcriteria, dynamic search)
{
        XmlDocument xdoc = new XmlDocument();
        XmlNodeList ndepartures = xdoc.SelectNodes("Destinations/Departure");
        string sFinalDeparture = objsearchcriteria.DepartureAirport.ToUpper();

        for (int i = 0; i < objsearchcriteria.DepartureAirport.Split('|').Length; i++)
        {

            for (int j = 0; j < ndepartures.Count; j++)
            {
                if (objsearchcriteria.DepartureAirport.Split('|')[i].ToUpper() == ndepartures[j]["Name"].InnerText.ToUpper())
                {
                    if (!sFinalDeparture.Contains(objsearchcriteria.DepartureAirport.Split('|')[i].ToUpper()))
                        sFinalDeparture += objsearchcriteria.DepartureAirport.Split('|')[i].ToUpper() + "|";

                    break;
                }
            }
        }
        return sFinalDeparture;
    }    

我想让这段代码更有效率，比如不使用循环，而是使用 Contains 或 Any 函数进行比较。请帮帮我好吗？

Answer 1

我认为您可以用这种可读且高效的 LINQ 方法替换整个方法:

public string HGSearchNew(HolidayFeedService.PackageHolidays.SearchCriteria objsearchcriteria)
{
    XmlDocument xdoc = new XmlDocument();
    XmlNodeList ndepartures = xdoc.SelectNodes("Destinations/Departure");
    string[] departureTokens = objsearchcriteria.DepartureAirport.Split('|');

    var matches = ndepartures.Cast<XmlNode>()
        .Select(node => node.Name)
        .Intersect(departureTokens, StringComparer.InvariantCultureIgnoreCase);

    return string.Join("|", matches);
}