30秒学会 C# 片段 – None

Returns true if the provided predicate function returns false for all elements in a collection, false otherwise.

Use IEnumerable.ToArray(), Array.Exists() to test if all elements in the collection return false based on the predicate function, match.
Omit the predicate function, match, to use the overload that checks if each value is null by default.

代码实现

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

public static partial class _30s 
{
  public static bool None<T>(IEnumerable<T> data, Predicate<T> match) 
  {
    return !Array.Exists(data.ToArray(), match);
  }
  public static bool None<T>(IEnumerable<T> data) 
  {
    return Array.Exists(data.ToArray(), val => val == null);
  }
}

使用样例

int[] nums = { 4, 2, 3 };

_30s.None(nums, x => x < 0); // true
_30s.None(nums); // false