Regex:php的密码验证

我正在对我的新项目进行密码验证。我想使用php preg_match（）函数在正则表达式模式上转换以下规则：

• 接受所有字符
• 除了空格
• 至少4个字符
• 最多20个字符

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提前谢谢你

试试这个

(?s)^(\S{4,20})$

解释

"(?s)" +     // Match the remainder of the regex with the options: dot matches newline (s)
"^" +        // Assert position at the beginning of the string
"(" +        // Match the regular expression below and capture its match into backreference number 1
   "\\S" +       // Match a single character that is a “non-whitespace character”
      "{4,20}" +      // Between 4 and 20 times, as many times as possible, giving back as needed (greedy)
")" +
"$"          // Assert position at the end of the string (or before the line break at the end of the string, if any)

---

试试这个

(?s)^(\S{4,20})$

解释

"(?s)" +     // Match the remainder of the regex with the options: dot matches newline (s)
"^" +        // Assert position at the beginning of the string
"(" +        // Match the regular expression below and capture its match into backreference number 1
   "\\S" +       // Match a single character that is a “non-whitespace character”
      "{4,20}" +      // Between 4 and 20 times, as many times as possible, giving back as needed (greedy)
")" +
"$"          // Assert position at the end of the string (or before the line break at the end of the string, if any)

见