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

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