英文:
Regular Expression for not allowing two consecutive special characters and also not in beginning and end
问题
以下是您要的翻译内容：
我正在寻找一个用于字符串的正则表达式，以满足以下条件：
- 只包含 A-Z、a-z、0-9、_、-、.
- 不以 _、-、. 开头或结尾。
- 不包含连续的特殊字符或它们的组合。
- 长度最大为 36，最小为 1。
正确示例：
abcd-efgH
1
a
123
abc
abc-asd-123-asd_asd.asd
错误示例：
-
abc-_asd
abc.
abc.-asd
123123-123123-ads--asd
091-asdsad---
我在周围搜索并找到了以下内容：
/^(?!.*[^\na-z0-9]{2})(?=.*[a-z0-9]$)[a-z0-9].*$/gim
但这允许所有特殊字符，而不仅仅是我检查的这三个。
英文:
I'm looking for a regex for a string to
- Contain only A-Z a-z 0-9 _ - .
- Not begin/end with _ - .
- Not containing consecutive special characters or their combination
- Max 36 length, minimum 1
Right
abcd-efgH
1
a
123
abc
abc-asd-123-asd_asd.asd
Wrong:
-
abc-_asd
abc.
abc.-asd
123123-123123-ads--asd
091-asdsad---
I seearched around and got this :-
/^(?!.*[^\na-z0-9]{2})(?=.*[a-z0-9]$)[a-z0-9].*$/gim
but this allows all special characters and not just the 3 that i checek
答案1
得分: 5
你可以在这个正则表达式中使用3个零宽断言：
^(?![-_.])(?!.*[-_.]{2})(?!.*[-_.]$)[-\w.]{1,36}$
正则表达式详解：
^：开头(?![-_.])：负向前瞻，不允许在开头出现[-_.](?!.*[-_.]{2})：负向前瞻，不允许任何地方出现连续的两个[-_.](?!.*[-_.]$)：负向前瞻，不允许在结尾出现[-_.][-\w.]{1,36}：匹配一个[-a-zA-Z0-9_.]字符，最少1个，最多36个$：结尾
英文:
You may use this regex with 3 lookaheads:
^(?![-_.])(?!.*[-_.]{2})(?!.*[-_.]$)[-\w.]{1,36}$
RegEx Details:
^: Start(?![-_.]): Negative lookahead to disallow[-_.]at the start(?!.*[-_.]{2}): Negative lookahead to disallow 2 consecutive[-_.]anywhere(?!.*[-_.]$): Negative lookahead to disallow[-_.]at the end[-\w.]{1,36}: Match a[-a-zA-Z0-9_.]character, min: 1, max: 36$: End
答案2
得分: 1
你是说类似于：
/^(?!.{37,})[a-z\d]+(?:[-._][a-z\d]+)*$/gim
查看在线演示[这里](https://regex101.com/r/10bmbN/6)
---
* `^` - 字符串起始锚点。
* `(?!.{37,})` - 负向先行断言，限制最少37个字符。
* `[a-z\d]+` - 至少一个字符在这个字符组内。
* `(?:` - 打开非捕获组。
* `[-._]` - 单个字符在这个字符组内。
* `[a-z\d]+` - 至少一个字符在这个字符组内。
* `)*` - 关闭非捕获组并允许匹配零次或多次。
* `$` - 字符串结束锚点。
英文:
Do you mean something like:
/^(?!.{37,})[a-z\d]+(?:[-._][a-z\d]+)*$/gim
See the online demo
^- Start string ancor.(?!.{37,})- Negative lookahead for 37 characters or more.[a-z\d]+- At least a single character within this character group.(?:- Open non-capturing group.[-._]- A single character within this character group.[a-z\d]+- At least a single character within this character group.)*- Close non-capturing group and match it zero or more times.
$- End string ancor.
答案3
得分: 0
我认为解决这个问题最简单、直接且直观逻辑的方法如下：
/^([a-z\d]|(?<![-_])(?<!^)[-_](?!$)){2,36}$/gim
解释非常简单。
第一个字符可以是字母或数字 或者（|）第一个字符可以是 _ 或 -，因为前一个字符
a) 不是 _ 也不是 -。
前一个字符的条件在 负回顾后查找 中：(?<![-_])
这意味着，使用当前光标位置，负回顾后查找（由 (?<! P) 模式表示，其中 P 是模式），只有在模式 P 不匹配时才可以（PS：回顾后查找不移动光标）
在这种情况下，模式 P 就是 [-_]。如果 P 后面不是 - 或 _，那么 - 或 _ 就是一个可选项！
b) _ 或 - 不在开头
紧接着我们又有一个只测试文本开头的负回顾后查找。P 就是 ^(表示文本开头的锚点)。负回顾后查找部分是 (?<!^)（P 就是 ^）
c) _ 或 - 不在结尾
最后，我们有一个负前瞻后出现在 [-_] 实际模式之后。唯一的语法差异是剪切字符 <（?P，其中 P 是模式）。现在，正则表达式处理在向前搜索模式 P，而不移动光标。如果模式失败，没关系（负面的！）
在这种情况下，我们有 (?!$)，其中 P 是 $，表示文本末尾的锚点。
例如：
ABCDEFGHIJKLMNOPQRSTU-XYZ01234_56789 匹配
但 ABCDEFGHIJKLMNOPQRSTU-_XYZ0123456789 不匹配
也不匹配 ABCDEFGHIJKLMNOPQRSTU-XYZ012345678_
也不匹配 _BCDEFGHIJKLMNOPQRSTU-XYZ0123456789
在此在线查看 此处：
英文:
I think the simplest and most direct way to solve this problem, in an intuitive and logical way, is the following:
/^([a-z\d]|(?<![-_])(?<!^)[-_](?!$)){2,36}$/gim
The explanation is pretty simple.
The first char can be letter or digit OR (|) the first character can be additionally be _ or -, since the previous char
a) is not _ neither -.
The previous char condition is in the negative lookbehind: (?<![-_])
It means, using the current cursor position, a negative look behind (represented by (?<! P) model, where P is a pattern) and it's ok just if pattern P don't (negative) fit (PS: Lookbehind don't move the cursor)
In this case, pattern P is just [-_]. If P behind is not - neither _, it means that - or _ are allowed as a option!
b) _ ou - is not in the start
Right after that we have another negative look behind that tests only the beginning of the text. P is just ^(the anchor that indicates start of the text). The look behind piece is (?<!^) (P is just ^)
c) _ ou - is not in the end
Finally we have a negative look forward, but is appears after [-_] real pattern. The only syntax difference is cut "<" character (?!P, where P is the pattern). Now, the regex processing is search forward for the pattern P, without move the cursor. If the pattern fail is OK (negative!)
In the case, we have (?!$), where P is $, the anchor that indicates the end of the text.
for example:
ABCDEFGHIJKLMNOPQRSTU-XYZ01234_56789 matches
but ABCDEFGHIJKLMNOPQRSTU-_XYZ0123456789 doesn't match
neither ABCDEFGHIJKLMNOPQRSTU-XYZ012345678_
neither _BCDEFGHIJKLMNOPQRSTU-XYZ0123456789
See online here:
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论