用于接受字母数字字符（6-10 个字符）的正则表达式 .NET、C#
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Regular expression for accepting alphanumeric characters (6-10 chars) .NET, C#
提问by Madhu
I am building a user registration form using C# with .NET. I have a requirement to validate user entered password fields. Validation requirement is as below.
我正在使用 C# 和 .NET 构建用户注册表。我需要验证用户输入的密码字段。验证要求如下。
- It should be alphanumeric (a-z , A-Z , 0-9)
- It should accept 6-10 characters (minimum 6 characters, maximum 10 characters)
- With at least 1 alphabet and number (example:
stack1over)
- 它应该是字母数字 (az , AZ , 0-9)
- 它应该接受 6-10 个字符（最少 6 个字符，最多 10 个字符）
- 与至少1字母和数字（例如：
stack1over）
I am using a regular expression as below.
我正在使用如下的正则表达式。
^([a-zA-Z0-9]{6,10})$
It satisfies my first 2 conditions. It fails when I enter only characters or numbers.
它满足我的前两个条件。当我只输入字符或数字时，它会失败。
采纳答案by paxdiablo
Pass it through multiple regexes if you can. It'll be a lot cleaner than those look-ahead monstrosities :-)
如果可以，请通过多个正则表达式传递它。它会比那些超前的怪物干净得多:-)
^[a-zA-Z0-9]{6,10}$
[a-zA-Z]
[0-9]
Though some might consider it clever, it's not necessary to do everythingwith a single regex (or even with any regex, sometimes - just witness the people who want a regex to detect numbers between 75 and 4093).
尽管有些人可能会认为这是聪明的，它没有必要做的一切与一个正则表达式（或者甚至正则表达式的任何，有时-只是见证谁想要一个正则表达式75和4093之间检测数的人）。
Would you rather see some nice clean code like:
你更愿意看到一些漂亮干净的代码，比如：
if not checkRegex(str,"^[0-9]+$")
return false
val = string_to_int(str);
return (val >= 75) and (val <= 4093)
or something like:
或类似的东西：
return checkRegex(str,"^7[5-9]$|^[89][0-9]$|^[1-9][0-9][0-9]$|^[1-3][0-9][0-9][0-9]$|^40[0-8][0-9]$|^409[0-3]$")
I know which one I'dprefer to maintain :-)
我知道我更喜欢维护哪一个:-)
回答by Amarghosh
Use positive lookahead
使用正向前瞻
^(?=.*[a-zA-Z])(?=.*[0-9])[a-zA-Z0-9]{6,10}$
Look arounds are also called zero-width assertions. They are zero-width just like the start and end of line (
^,$). The difference is that lookarounds will actually match characters, but then give up the match and only return the result: match or no match. That is why they are called "assertions". They do not consume characters in the string, but only assert whether a match is possible or not.
环顾四周也称为零宽度断言。它们的宽度为零，就像行 (
^,$)的开始和结束一样。不同之处在于环视实际上会匹配字符，但随后放弃匹配并仅返回结果：匹配或不匹配。这就是为什么它们被称为“断言”。它们不消耗字符串中的字符，而只断言匹配是否可能。
The syntax for look around:
环顾四周的语法：
(?=REGEX)Positive lookahead(?!REGEX)Negative lookahead(?<=REGEX)Positive lookbehind(?<!REGEX)Negative lookbehind
(?=REGEX)正向前瞻(?!REGEX)负前瞻(?<=REGEX)正面回顾(?<!REGEX)负面回顾
回答by Brock Hensley
string r = @"^(?=.*[A-Za-z])(?=.*[0-9])[A-Za-z0-9]{6,10}$";
Regex x = new Regex(r);
var z = x.IsMatch(password);
http://www.regular-expressions.info/refadv.html
http://www.regular-expressions.info/refadv.html
