`转换列表与LT;字符串＆GT;`以逗号分隔的字符串 [英] Convert `List<string>` to comma-separated string

问题描述

有没有转换的快捷方式列表＆LT;串＆GT; 来用逗号分隔的字符串在C＃

Is there a fast way to convert List<string> to a comma-separated string in C#?

我不喜欢这样，但也许有一个更快或更有效的方式？

I do it like this but Maybe there is a faster or more efficient way?

List<string> ls = new List<string>();
ls.Add("one");
ls.Add("two");
string type = string.Join(",", ls.ToArray());

PS：搜索这个网站，但大多数解决方案是Java或Python

PS: Searched on this site but most solutions are for Java or Python

推荐答案

在.NET 4中，你不需要 ToArray的（）通话 - 的 的string.join 超载接受的IEnumerable＆LT; T＆GT; 或只是的IEnumerable＆LT;字符串方式＆gt;

In .NET 4 you don't need the ToArray() call - string.Join is overloaded to accept IEnumerable<T> or just IEnumerable<string>.

有.NET 4之前做的可能更有效的方法，但你真的需要它们？这实际上是在你的code瓶颈？

There are potentially more efficient ways of doing it before .NET 4, but do you really need them? Is this actually a bottleneck in your code?

您的可能的遍历目录，制定出最终的大小，分配的StringBuilder 完全正确的尺寸，然后执行加入自己。这将避免额外的阵列在建的没有理由 - 但它不会节省很多时间，这将是一个的很多的多个code

You could iterate over the list, work out the final size, allocate a StringBuilder of exactly the right size, then do the join yourself. That would avoid the extra array being built for little reason - but it wouldn't save much time and it would be a lot more code.

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