C＃：在字符串中查找字符串的实例 [英] C#: finding instances of a string within a string

问题描述

假如我有字符串1,2和3或4，并希望创建一个字符串数组，其中包含所有子AND或OR，依次字符串中找到。

Suppose I had the string "1 AND 2 AND 3 OR 4", and want to create an array of strings that contains all substrings "AND" or "OR", in order, found within the string.

所以上面的字符串将返回一个字符串数组{和，和，或}

So the above string would return a string array of {"AND", "AND", "OR"}.

？什么是书面的一个聪明的办法

What would be a smart way of writing that?

编辑：
使用C＃2.0 +

Using C# 2.0+,

string rule = "1 AND 2 AND 3 OR 4";
string pattern = "(AND|OR)";
string[] conditions = Regex.Split(rule, pattern);

给我{1，和，2，和，3 ，或，4}，这是不太我后。我怎样才能降低到AND和OR只？

gives me {"1", "AND", "2", "AND", "3", "OR", "4"}, which isn't quite what I'm after. How can I reduce that to the ANDs and ORs only?

推荐答案

这正则表达式（.NET），似乎做你想要什么。您正在寻找在指数= 1组中的比赛（多）：

This regex (.NET) seems to do what you want. You're looking for the matches (multiple) in the group at index=1:

.*?((AND)|(OR))*.*?

修改我测试过以下，似乎做什么你想。它更多的行比我想的，但它在一个纯粹的正则表达式的方式接近的任务（这恕我直言，是你应该做的事情）：

EDIT I've tested the following and it seems to do what you want. It's more lines than i would like but it approaches the task in a purely regex fashion (which IMHO is what you should be doing):

        string text = "1 AND 2 AND 3 OR 4";
        string pattern = @"AND|OR";

        Regex r = new Regex(pattern, RegexOptions.IgnoreCase);

        Match m = r.Match(text);
        ArrayList results = new ArrayList();
        while (m.Success)
        {
            results.Add(m.Groups[0].Value);

            m = m.NextMatch();
        }

        string[] matchesStringArray = (string[])results.ToArray(typeof(string));

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