如何从字典中获取MAX值？ [英] How to get MAX value from Dictionary?

问题描述

我有

Dictionary<Guid, DateTime> d = new Dictionary<Guid, DateTime>();

我如何获得 Guid MAX 值？

推荐答案

因为这是公认的答案，所以我ll尝试覆盖问题的所有可能含义：

Since this was the accepted answer, I'll try to cover every possible meaning of the question:

var dict = new Dictionary<string, int> { { "b", 3 }, { "a", 4 } };

// greatest key
var maxKey = dict.Keys.Max(); // "b"

// greatest value
var maxValue = dict.Values.Max(); // 4

// key of the greatest value
// 4 is the greatest value, and its key is "a", so "a" is the answer.
var keyOfMaxValue = dict.Aggregate((x, y) => x.Value > y.Value ? x : y).Key; // "a"

注意：该问题具有 System.Guid 作为键类型。询问什么是最大的GUID可能没有任何意义，因为它们仅是唯一的值，而不是表示任何可排序的概念。尽管如此，以上代码仍可用于支持> 运算符， string 和 int 。

Note: the question has System.Guid as the key type. It might not make sense to ask "what is the greatest GUID", since they are simply intended to be unique values, rather than represent any orderable concept. Nonetheless, the above code will work with any type that supports the > operator, string and int being chosen here for conciseness.

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