在C#中获取重叠的正则表达式匹配 [英] Getting overlapping regex matches in C#

问题描述

我有正则表达式 1(0 *)1 和测试字符串 1000010001

I have the regex 1(0*)1 and the test string 1000010001

我想进行2场比赛，但是我发现只有1场比赛:

I want to have 2 matches, but I find that only 1 gets found :

var regex = new Regex("1(0*)1");
var values = regex.Matches(intBinaryString);
// values only has 1 match

regexonline似乎同意: https://regex101.com/r/3J9Qxj/1

regexonline seems to agree : https://regex101.com/r/3J9Qxj/1

我在做什么错了?

推荐答案

您已经在第一个匹配中选择了第二个零前面的1.

You are already selecting the 1 in front of the second zero by the first match.

100001 0001
^^^^^^

这是第一场比赛.其余的只是 0001 ，与您的正则表达式不匹配.

This is the first match. The rest is just 0001 which does not match your regex.

如果您使用先行/后退，则可以避免这种行为:

You can circumvent this behavior if you are using lookaheads/lookbehinds:

(?<=1)(0*)(?=1)

在线示例

由于您无法在JavaScript中使用后备导航，仅使用一次前瞻就足以防止重叠:

Because you cannot use lookbehinds in JavaScript, it is enough to only use one lookahead, to prevent the overlapping:

1(0*)(?=1)

在线示例

以及您的 regex101 示例的提示:您没有添加全局标志，这会阻止多个选择.

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