提取使用正则表达式找到搜索关键字的部分字符串

Question

字符串看起来像

最大使用次数

A Borrower (or the Parent) may not deliver a Utilisation Request if as a result of the proposed Utilisation:<br/>
[10] or more Term Loans [(other than Incremental Company Loans)] would be outstanding; [or]<br/>
[15] or more Revolving Company Utilisations would be outstanding[; or<br/>
[20] or more Incremental Company Loans would be outstanding].<br/>
A Borrower (or the Parent) may not request that a Company A Loan [or an Incremental Company Loan] be divided if, as a result of the proposed division, [  25      ] or more Company A Loans [or [  50    ] or more Incremental Company Loans] would be outstanding.<br/>
[A Borrower (or the Parent) may not request that a Company B Loan or a Company C Loan be divided.]

预期输出：

[ 10 ] or more Term Loans [(other than Incremental Company Loans)] would be outstanding; 
[ 15 ] or more Revolving Company Utilisations would be outstanding[; or
[ 20 ] or more Incremental Company Loans would be outstanding].

我尝试的方法似乎不起作用

Regex = '.*other than Incremental Company Loans.*'

这将返回整个段落。可能还有其他方法可以做到这一点，但我们只能使用 REGEX 来做到这一点。

Answer 1

纯正则表达式方法可能不够，因为您可能想进一步用换行符替换<br/>，而且模式相当复杂：

(?<=^|<br/>)(?:(?!<br/>).)*other than Incremental Company Loans[\s\S]*?(?=[.;]<br/>|$)

见regex demo

匹配：

• (?<=^|<br/>) - 以字符串开头或 <br/> 子字符串开头的位置
• (?:(?!<br/>).)* - 任何字符，0+ 次，不以 <br/> 子字符串开头
• other than Incremental Company Loans - 搜索字符串
• [\s\S]*? - 任何 0+ 个字符，尽可能少
• (?=[.;]<br/>|$) - 紧跟在 . 或 ; 后面紧跟 <br/> 或字符串结尾。

当您使用 C# 编写代码时，您可以使用可读性强且易于调整的non-regex solution：

var s = "A Borrower (or the Parent) may not deliver a Utilisation Request if as a result of the proposed Utilisation:<br/>[10] or more Term Loans [(other than Incremental Company Loans)] would be outstanding; [or]<br/>[15] or more Revolving Company Utilisations would be outstanding[; or<br/>[20] or more Incremental Company Loans would be outstanding].<br/>A Borrower (or the Parent) may not request that a Company A Loan [or an Incremental Company Loan] be divided if, as a result of the proposed division, [  25      ] or more Company A Loans [or [  50    ] or more Incremental Company Loans] would be outstanding.<br/>[A Borrower (or the Parent) may not request that a Company B Loan or a Company C Loan be divided.]";
var result = s.Split(new[] {"<br/>"}, StringSplitOptions.None)
    .SkipWhile(x => !x.Contains("other than Incremental Company Loans"))
    .MagicTakeWhile(x => !x.EndsWith(".") && !x.EndsWith(";"));
Console.WriteLine(string.Join("\n", result));

输出：

[10] or more Term Loans [(other than Incremental Company Loans)] would be outstanding; [or]
[15] or more Revolving Company Utilisations would be outstanding[; or
[20] or more Incremental Company Loans would be outstanding].

MagicTakeWhile 方法是从TakeWhile, but get the element that stopped it also 借来的。它需要项目直到满足条件包括停止满足条件的最后一个项目。