正则表达式来限制组中的特定字符 [英] Regex to limit specific characters within a group

问题描述

我努力改变当前的模式:

I struggle to change my current pattern:

^[\\\/0-9]{5,10}$

^[\\\/0-9]{5,10}$

检查输入内容是否由5-10个数字，斜杠或反斜杠组成. 我想将斜杠和反斜杠的总数最多限制为两个.

Which checks if input comprises of 5-10 numbers, slashes or backslashes. I would like to limit total slash and backslash count to two at most.

例如更改后 12345/\\9 无效:

e.g. 12345/\\9 should not be valid after the change:

我尝试将它们解剖成一个单独的组，例如 ^([\\\/]{0,2}[0-9]){5,10}$ ，但是匹配错误.

I tried dissecting them into a separate group like so ^([\\\/]{0,2}[0-9]){5,10}$ but am getting wrong matches.

推荐答案

您可以使用锚定在测试两个全局条件"之一的字符串开头的超前模式来构建模式:字符串长度或斜杠数

You can build a pattern using a lookahead anchored at the start of the string that tests one of the two "global conditions": the string length or number of slashes.

要限制斜杠的数量，您可以这样设计图案:

To limit the number of slashes you can design your pattern like this:

^[0-9]*(?:[/\\][0-9]*){0,2}$

然后，您只需要在超前断言(?=...)中添加字符串长度的条件即可:

Then you only have to add the condition for the string length in the lookahead assertion (?=...):

^(?=.{5,10}$)[0-9]*(?:[/\\][0-9]*){0,2}$

(请注意，只有当模式由斜杠分隔时，才必须转义正斜杠.否则，斜杠不是特殊字符.)

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