让我们说我有一个文本，我想找到每个逗号的位置。字符串，一个较短的版本，应该是这样的：

Let's say I have a text and I want to locate the positions of each comma. The string, a shorter version, would look like this:

string s = "A lot, of text, with commas, here and,there";

在理想情况下，我会用这样的：

Ideally, I would use something like:

int[] i = s.indexOf(',');

但因为只的indexOf返回第一个逗号，而不是我做的：

but since indexOf only returns the first comma, I instead do:

List<int> list = new List<int>();
for (int i = 0; i < s.Length; i++)
{
   if (s[i] == ',')
      list.Add(i);
}

是否有替代，这样做的更优化的方式？

Is there an alternative, more optimized way of doing this?

推荐答案

您可以使用 Regex.Matches（字符串，字符串）方法。这将返回一个MatchCollection，然后你可以决定Match.Index。 MSDN有一个很好的例子，

You could use Regex.Matches(string, string) method. This will return a MatchCollection and then you could determine the Match.Index. MSDN has a good example,

使用系统; 使用System.Text.RegularEx pressions;

using System; using System.Text.RegularExpressions;

public class Example
{
   public static void Main()
   {
      string pattern = @"\b\w+es\b";
      string sentence = "Who writes these notes?";

      foreach (Match match in Regex.Matches(sentence, pattern))
         Console.WriteLine("Found '{0}' at position {1}", 
                           match.Value, match.Index);
   }
}
// The example displays the following output:
//       Found 'writes' at position 4
//       Found 'notes' at position 17