Question

此验证适用于允许使用字母数字字符，空格和短划线，但我无法将最大长度设置为23。

正则表达式：的（^ \ W + \ S *（ - ）（\ S * \ W + \ S *）（\ W +）$）{0,23}

我需要通过的案件：

Winston1-Salem6
温斯顿塞勒姆
Winston Salem
1-TWO3
word2 with space

我需要失败的案例：

-Newberty洛杉矶 -
12345678901234567890123444

Answer 1

单独检查长度可能更方便，但您可以使用前瞻来确认整个表达式介于0到23个字符之间。

(?=^.{0,23}$)(^\w+\s*(-?)(\s*\w+\s*)(\w+)$)

http://rubular.com/r/GVIbG8hDKz

Answer 2

只需使用前瞻来断言最大长度：

(?=^.{1,23}$)^\w+\s*(-?)(\s*\w+\s*)(\w+)$

Demo

或者负面的前瞻也是如此：

(?!^.{24,})^\w+\s*(-?)(\s*\w+\s*)(\w+)$

Demo

lookaheads现代正则表达式

支持可变宽度most

Answer 3

正则表达式不能像你想要的那样匹配总长度。

使用

procedure TForm2.TMSFMXWebBrowser1BeforeNavigate(Sender: TObject;
var Params: TTMSFMXCustomWebBrowserBeforeNavigateParams);
begin
// Get your result from Params.URL and cancel via Params.Cancel := True;
end;

并在比赛结束后手动检查组＃1的长度。

Answer 4

^(?!(^-|-$|.{24,})).*

Winston1-Salem6 - PASS
Winston-Salem - PASS
Winston Salem - PASS
1-two3 - PASS
word2 with space - PASS
-Newberty-Los-  - FAIL 
12345678901234567890123444 - FAIL

演示 https://regex101.com/r/eM3qR9/2

正则表达式解释：

^(?!(^-|-$|.{24,})).*

Assert position at the beginning of the string «^»
Assert that it is impossible to match the regex below starting at this position (negative lookahead) «(?!(^-|-$|.{24,}))»
   Match the regex below and capture its match into backreference number 1 «(^-|-$|.{24,})»
      Match this alternative «^-»
         Assert position at the beginning of the string «^»
         Match the character “-” literally «-»
      Or match this alternative «-$»
         Match the character “-” literally «-»
         Assert position at the end of the string, or before the line break at the end of the string, if any «$»
      Or match this alternative «.{24,}»
         Match any single character that is NOT a line break character «.{23,}»
            Between 24 and unlimited times, as many times as possible, giving back as needed (greedy) «{24,}»
Match any single character that is NOT a line break character «.*»
   Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»

如何设置此正则表达式的最大长度？

4 个答案: