以下约束的正则表达式是什么？

Question

我需要一个用于密码的字符串的正则表达式，该字符串至少包含以下四种类型中的三个字符：

• 英文小写字符(a到z)。
• 英文大写字符(A到Z)。
• 基数为10位(0到9)。
• 非字母数字字符(例如!，$，#，%)。

并且应该至少包含8个字符。

Answer 1

正确回答我的问题：

正则表达式：

^((?=.\d)(?=.a-z)(?=.A-Z)|(?=.a-z)(?=.A-Z)(?=.^\w\d\s)|(?=.\d)(?=.A-Z)(?=.^\w\d\s)|(?=.\d)(?=.a-z)(?=.^\w\d\s)).{8,30}$

谢谢。

Answer 2

regex的扩展PCRE版本：

/^(?:
  (?=.*[a-z])         # look ahead: at least one from a-z
  (?=.*[A-Z])         # look ahead: at least one from A-Z
  (?=.*[0-9])         # look ahead: at least one from 0-9
  |                   # or...
  (?=.*[a-z])         # look ahead: at least one from a-z
  (?=.*[A-Z])         # look ahead: at least one from A-Z
  (?=.*[^a-zA-Z0-9])  # look ahead: at least one from special chars
  |                   # or...
  (?=.*[a-z])         # look ahead: at least one from a-z
  (?=.*[0-9])         # look ahead: at least one from 0-9
  (?=.*[^a-zA-Z0-9])  # look ahead: at least one from special chars
  |                   # or...
  (?=.*[A-Z])         # look ahead: at least one from A-Z
  (?=.*[0-9])         # look ahead: at least one from 0-9
  (?=.*[^a-zA-Z0-9])  # look ahead: at least one from special chars
  )
  \S{8,}              # at least 8 non-spaces
$/x

Answer 3

首先，下面是帕克斯辉绿罗代码的C#翻译：

public bool Validate(string input)
{
    if (input == null || input.Length < 8)
        return false;
    int counter = 0;
    if (input.Any(Char.IsLower)) counter++;
    if (input.Any(Char.IsUpper)) counter++;
    if (input.Any(Char.IsDigit)) counter++;
    if (input.Any(c => Char.IsPunctuation(c) || Char.IsSymbol(c))) counter++;
    return counter >= 3;
}

如果坚持使用正则表达式，则可以使用类似于.NET Regex平衡组的乐趣上的模式

^
(?=.*[a-z](?<Counter>))?
(?=.*[A-Z](?<Counter>))?
(?=.*[0-9](?<Counter>))?
(?=.*[^a-zA-Z0-9](?<Counter>))?
(?<-Counter>){3}   # check we've had at least 3 groups
.{8}

您还可以允许Unicode类

^
(?=.*\p{Ll}(?<Counter>))?
(?=.*\p{Lu}(?<Counter>))?
(?=.*\p{Nd}(?<Counter>))?
(?=.*[\p{S}\p{P}](?<Counter>))?
(?<-Counter>){3}
.{8}