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;
    }    

我想使此代码高效，而不是使用循环，使用Contains或Any函数进行比较。 请帮我吗？

Answer 1

我认为您可以用这种可读高效的LINQ方法代替整个方法：

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);
}