带值的 SortedList 和带 lambda 的简化循环

发布于 2024-12-31 23:51:32 字数 587 浏览 1 评论 0原文

我这里有一段代码：

SortedList<char, int> alpha = new SortedList<char, int>();
List<string> A = new List<string>();
alpha.OrderByDescending(x => x.Value);
foreach (var a in alpha)
    A.Add(a.Key + ":" + a.Value);

alpha.OrderByDescending(x => x.Value); 不按值排序，而是按键排序。我可以知道代码有什么问题吗？
我可以简化一下：
foreach（alpha 中的 var a） A.Add(a.Key + ":" + a.Value);

到一个 lambda 语句中？类似的东西

alpha.ForEach(x => A.Add(a.Key + ":" + a.Value));

原文

I have a block of codes here:

SortedList<char, int> alpha = new SortedList<char, int>();
List<string> A = new List<string>();
alpha.OrderByDescending(x => x.Value);
foreach (var a in alpha)
    A.Add(a.Key + ":" + a.Value);

alpha.OrderByDescending(x => x.Value); doesn't sort by value, but sorts by key. May I know what's the problem with the code?
can I simplify:
foreach (var a in alpha) A.Add(a.Key + ":" + a.Value);

into one lambda statement? something like

alpha.ForEach(x => A.Add(a.Key + ":" + a.Value));

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故事灯 2025-01-07 23:51:32

语句 alpha.OrderByDescending(x => x.Value); 无效...Linq 运算符是惰性的，它们在您枚举其结果之前不会执行。由于您没有使用 OrderByDescending 的结果，它只是创建一个惰性序列，会生成按值排序的 alpha 项，< em>如果您枚举它...OrderByDescending 不会对集合进行排序，它只是从集合中返回已排序的项目序列，而不修改集合本身。

你应该这样做：

foreach (var a in alpha.OrderByDescending(x => x.Value))
    A.Add(a.Key + ":" + a.Value);

The statement alpha.OrderByDescending(x => x.Value); has no effect... Linq operators are lazy, they're not executed until you enumerate their result. Since you're not using the result of OrderByDescending, it just creates a lazy sequence that would yield the items of alpha sorted by value, if you enumerated it... OrderByDescending doesn't sort the collection, it just returns a sorted sequence of items from the collection, without modifying the collection itself.

You should do it like this:

foreach (var a in alpha.OrderByDescending(x => x.Value))
    A.Add(a.Key + ":" + a.Value);

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ヤ经典坏疍 2025-01-07 23:51:32

这可能有帮助：

SortedList<char, int> alpha = new SortedList<char, int>();
alpha.Add('B',1);
alpha.Add('A',2);
alpha.Add('C',3);
var A= alpha.OrderByDescending(a =>a.Value)
        .Select (a =>a.Key+":"+a.Value)
        .ToList();

This might help:

SortedList<char, int> alpha = new SortedList<char, int>();
alpha.Add('B',1);
alpha.Add('A',2);
alpha.Add('C',3);
var A= alpha.OrderByDescending(a =>a.Value)
        .Select (a =>a.Key+":"+a.Value)
        .ToList();

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~没有更多了~