正则表达式:获取每个在其之前或之后没有其他数字的数字 [英] Regex: get every number that doesn't has an other number before or after itself

问题描述

我必须做的事情是提取每个单个"数字，在它之前或之后没有另一个数字.然后我必须用一个数字替换这个数字，该数字以 1 递增.

The thing that I have to do is to extract every 'single' number, that doesn't has another number right before or after itself. Then I have to replace this number with an number, that is incremented with 1.

我现在想要一个从字符串中获取每个数字的正则表达式，在它之前或之后没有另一个数字.

I now want to a Regex that gets every single number from a string, that doesn't has another number right before or after itself.

例如:

From this string, I just want the '1': "Klasse 1a 14/15" the result should look like "Klasse 2a 14/15"

From this string, I just want the '5': "5/66" the result should look like "6/66"

From this string, I want the '1', '2' and '3': "1/2/3" and the result should look like "2/3/4"

From this string, I just want the '4': "4. Klasse" and the result should look like "5. Klasse"

From this string, I don't want to get anything: "Klasse 99" and the result will remain "Klasse 99"

我目前拥有的是这个正则表达式:

What I have at the Moment is this Regex:

[\D*](\d{1})[\D*]

还有这个方法:

internal string GenerateFollowingSubjectGradeTitle(string currentGradeTitle)
    {
        var followingGradeTitle = string.Format("{0}{1}{0}", "_", currentGradeTitle);

        var regex = new Regex(@"[\D*](\d){1}[\D*] /gm");

        var matches = regex.Matches(followingGradeTitle);

        if (matches.Count > 0)
        {
            for (var i = 0; i < matches.Count; i++)
            {
                var exactmatch = matches[i].Groups[1].Value;
                var groupmatch = matches[i].Groups[0].Value;

                var intmatch = 0;
                if (int.TryParse(exactmatch, out intmatch))
                {
                    var groupreplace = groupmatch.Replace(exactmatch, (intmatch + 1).ToString());
                    followingGradeTitle = followingGradeTitle.Replace(groupmatch, groupreplace);
                }
            }
        }

        return followingGradeTitle.Substring(1, followingGradeTitle.Length - 2);
    }

..它主要工作但不是每次都有效.在1/2/3"中，我只得到 1 和 3，但我也需要 2.

..and it works mostly but not everytime. In "1/2/3" I just get the 1 and the 3, but I need the 2 as well.

我知道我的尝试不是最好的方法，如果您有更好的解决方案，请告诉我:)

I know my attempt is not the best way, if you have better solutions, let me know :)

有什么建议吗?

推荐答案

您可以尝试以下基于正则表达式的负面环视.

You could try the below negative lookarounds based regex.

(?<!\d)\d(?!\d)

演示

或

如果您正在运行 javascript，这将起作用.从组索引 1 中选择您想要的数字.环视是不会消耗任何字符的断言.

This would work if you're running javascript. Pick the number you want from group index 1. Lookarounds are assertion which won't consume any character.

(?:^|\D)(\d)(?=\D|$)

演示

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