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  • linq count() sum() Min() Max() Average() 用法

    #region 用Count()得出查询结果的个数
    Response.Write("<hr>用Count()得出查询结果的个数<br>");
    var langCount = (from s in GetStudents()
    select s.Language)
    .Distinct()
    .Count();
    Response.Write(string.Format("<div class='result'>{0}</div>", langCount));
    #endregion
    #region 用Count()的Lambda表达式满足条件的元素个数
    Response.Write("<hr>用Count()得出查询结果的个数<br>");
    var ageCoun = (from s in GetStudents()
    select s.Age)
    .Count(a=>a>22);
    Response.Write(string.Format("<div class='result'>{0}</div>", ageCoun));
    #endregion
    #region 用Sum()将查询结果相加
    Response.Write("<hr>用Sum()将查询结果相加<br>");
    var ageSum = (from s in GetStudents()
    select s.Age)
    .Sum();
    //var ageSum = GetStudents().Sum(s=>s.Age);
    Response.Write(string.Format("<div class='result'>{0}</div>", ageSum));
    #endregion
    #region 用Min()得出查询结果的最小值
    Response.Write("<hr>用Min()得出查询结果的最小值<br>");
    var ageMin = (from s in GetStudents()
    select s.Age)
    .Min();
    //var ageMin = GetStudents().Min(s => s.Age);
    Response.Write(string.Format("<div class='result'>{0}</div>", ageMin));
    #endregion
    #region 用Max()得出查询结果的最大值
    Response.Write("<hr>用Max()得出查询结果的最大值<br>");
    var ageMax = (from s in GetStudents()
    select s.Age)
    .Max();
    //var ageMax = GetStudents().Max(s => s.Age);
    Response.Write(string.Format("<div class='result'>{0}</div>", ageMax));
    #endregion
    #region 用Average()得出查询结果的平均值
    Response.Write("<hr>用Average()得出查询结果的平均值<br>");
    var ageAverage = (from s in GetStudents()
    select s.Age)
    .Average();
    //var ageAverage = GetStudents().Average(s => s.Age);
    Response.Write(string.Format("<div class='result'>{0}</div>", ageAverage));
    #endregion
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  • 原文地址:https://www.cnblogs.com/yannis/p/2311770.html
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