30秒学会 C# 片段 – MaxBy

Returns the maximum of a collection, after mapping each element to a value using the provided function.

Use IEnumerable.Select() to map each element to the value returned by the provided selector function, fn.
Use IEnumerable.Max() to get the maximum of the resulting values.

代码实现

using System.Collections.Generic;
using System.Linq;

public static partial class _30s
{
  public static double MaxBy<T>(IEnumerable<T> values, Func<T,int> fn)
  {
    return values.Select(fn).Max();
  }
}

使用样例

var p = new [] {
  new { a = 3, b = 2},
  new { a = 2, b = 1}
};

_30s.MaxBy(p, v => v.a); // 3
_30s.MaxBy(p, v => v.b); // 2