在c#字典中设置所有值的最佳方法是什么?

What's the best way to set all values in a C# Dictionary?

在c#字典中设置所有值的最好方法是什么?

Here is what I am doing now, but I'm sure there is a better/cleaner way to do this:

这是我现在正在做的，但我确信有更好的/更干净的方法可以做到:

Dictionary<string,bool> dict = GetDictionary();
var keys = dict.Keys.ToList();
for (int i = 0; i < keys.Count; i++)
{
    dict[keys[i]] = false;
}

I have tried some other ways with foreach, but I had errors.

我尝试了一些其他的方法，但我有错误。

7 个解决方案

#1

That is a reasonable approach, although I would prefer:

这是一种合理的做法，尽管我宁愿:

foreach (var key in dict.Keys.ToList())
{
    dict[key] = false;
}

The call to ToList() makes this work, since it's pulling out and (temporarily) saving the list of keys, so the iteration works.

对ToList()的调用使这个工作得以完成，因为它正在拉出并(临时)保存键列表，因此迭代可以工作。

#2

A one-line solution:

一行的解决方案:

dict = dict.ToDictionary(p => p.Key, p => false);

#3

If you aren't using tri-state bools, then you can use HashSet<string>, and call Clear() to set the values to "false".

如果您没有使用tristate bools，那么您可以使用HashSet ，并调用Clear()将值设置为“false”。

#4

I'm not sure if it's the best way but I was looking something on a single line and this worked for me

我不确定这是不是最好的方法，但我在一条直线上找了一些东西，这对我很有效

mydict.Keys.ToList().ForEach(k => mydict[k] = false);

#5

I profiled the difference between Billy's and Reed's solutions. Polaris878, take good note of the results and remember that premature optimization is the root of all evil ;-)

我分析了比利和里德的解决方案之间的区别。Polaris878，记下结果并记住，过早优化是万恶之源;

I rewrote the solutions in VB (because I'm currently programming in that language) and used int keys (for simplicity), otherwise it's the exact same code. I ran the code with a dictionary of 10 million entries with a value of "true" for each entry.

我用VB重写了解决方案(因为我目前正在用这种语言编程)，并使用int键(为了简单)，否则就是完全相同的代码。我使用一个包含1000万个条目的字典运行代码，每个条目的值为“true”。

Billy Witch Doctor's original solution:

比利巫医的原始解决方案:

Dim keys = dict.Keys.ToList
For i = 0 To keys.Count - 1
    dict(keys(i)) = False
Next

Elapsed milliseconds: 415

经过的毫秒:415

Reed Copsey's solution:

里德Copsey的解决办法:

For Each key In dict.Keys.ToList
    dict(key) = False
Next

Elapsed milliseconds: 395

经过的毫秒:395

So in that case the foreach is actually faster.

在这种情况下，foreach实际上更快。

#6

-2

You could just pull out the ToList() and iterate directly over the dictionary items

您可以提取ToList()并直接遍历字典项

Dictionary<string, bool> dict = GetDictionary();
foreach (var pair in dict) 
{
    dict[pair.Key] = false;
}

#7

-4

Do it the way you have it right now... foreach is slow. foreach may be cleaner, but you take too much of a performance hit using it.

按照你现在的方式去做……foreach是缓慢的。因为每一个都可能更干净，但是你使用它会造成性能损失。

Edit:
http://www.codeproject.com/KB/cs/foreach.aspx
http://www.madprops.org/blog/for-vs-foreach-performance/

编辑:http://www.codeproject.com/KB/cs/foreach.aspx http://www.madprops.org/blog/for-vs-foreach-performance/

#1