正則表達式以匹配字符串的第一個匹配項與最后一個匹配的字符串

Question

我有以下清單

Acid
stuff
goo
nasty
Probable
Acid
more stuff
Probable
Acid 
fff
ggg
Probable

我想匹配“酸”和“可能”之間的所有內容。 但是我的正則表達式僅匹配最后一個匹配項（ Acid,fff,ggg,Probable ）而不匹配第一個匹配項（ Acid,stuff, goo, nasty, Probable ）

調用類：

    public static void main(String[] args) throws IOException {


       PDFManager pdfManager = new PDFManager();
       pdfManager.setFilePath("MyFile.pdf");
       String s=pdfManager.ToText();


       if(s.contains("Thresholds")){

              BravoaltDoc_ExtractionNonDays Sum = new BravoaltDoc_ExtractionNonDays(s);
              Sum.ExtractSumNew(s);


   public class BravoaltDoc_ExtractionNonDays {
    String doc;
}}

    ArrayList<String> Day_arr = new ArrayList<String>();
    ArrayList<List<String>> Day_table2d = new ArrayList<List<String>>();
    String [] seTab3Landmarks=null;

    public BravoaltDoc_ExtractionNonDays(String doc) {
        this.doc=doc;
    }

    public String ExtractSumNew(String doc) {
        Pattern Tab3Landmarks_pattern = Pattern.compile("Acid?(.*?)Probable",Pattern.DOTALL);
        Matcher matcherTab3Landmarks_pattern = Tab3Landmarks_pattern.matcher(doc);
        while (matcherTab3Landmarks_pattern.find()) {
            doc=matcherTab3Landmarks_pattern.group(1);
            seTab3Landmarks=matcherTab3Landmarks_pattern.group(1).split("\\n|\\r");
        }
        for (String n:seTab3Landmarks){
            System.out.println(n);
        }
return docSlim;

    }

}

Answer 1

描述

此正則表達式將執行以下操作：

• 將以Acid開頭的子字符串匹配為Probable
• 需要Acid和Probable在自己的行。 如果它們嵌入在像gooProbablegoo這樣的字符串中間， gooProbablegoo它們將不匹配

對於此正則表達式，我使用了Case Insenstive標志，而Dot匹配了新行Flag。

(?:\r|\n|\A)\s*Acid\s*?[\r\n].*?[\r\n]\s*Probable\s*?(?:\r|\n|\Z)

例

示范文本

注意：第三行中的困難邊緣情況。

Acid
stuff
gooProbablegoo
nasty
Probable
Acid
more stuff
Probable
Acid
fff
ggg
Probable

火柴

[0][0] = Acid
stuff
gooProbablegoo
nasty
Probable

[1][0] = 
Acid
more stuff
Probable

[2][0] = 
Acid
fff
ggg
Probable

講解

NODE                     EXPLANATION
----------------------------------------------------------------------
  (?:                      group, but do not capture:
----------------------------------------------------------------------
    \r                       '\r' (carriage return)
----------------------------------------------------------------------
   |                        OR
----------------------------------------------------------------------
    \n                       '\n' (newline)
----------------------------------------------------------------------
   |                        OR
----------------------------------------------------------------------
    \A                       the beginning of the string
----------------------------------------------------------------------
  )                        end of grouping
----------------------------------------------------------------------
  \s*                      whitespace (\n, \r, \t, \f, and " ") (0 or
                           more times (matching the most amount
                           possible))
----------------------------------------------------------------------
  Acid                     'Acid'
----------------------------------------------------------------------
  \s*?                     whitespace (\n, \r, \t, \f, and " ") (0 or
                           more times (matching the least amount
                           possible))
----------------------------------------------------------------------
  [\r\n]                   any character of: '\r' (carriage return),
                           '\n' (newline)
----------------------------------------------------------------------
  .*?                      any character (0 or more times (matching
                           the least amount possible))
----------------------------------------------------------------------
  [\r\n]                   any character of: '\r' (carriage return),
                           '\n' (newline)
----------------------------------------------------------------------
  \s*                      whitespace (\n, \r, \t, \f, and " ") (0 or
                           more times (matching the most amount
                           possible))
----------------------------------------------------------------------
  Probable                 'Probable'
----------------------------------------------------------------------
  \s*?                     whitespace (\n, \r, \t, \f, and " ") (0 or
                           more times (matching the least amount
                           possible))
----------------------------------------------------------------------
  (?:                      group, but do not capture:
----------------------------------------------------------------------
    \r                       '\r' (carriage return)
----------------------------------------------------------------------
   |                        OR
----------------------------------------------------------------------
    \n                       '\n' (newline)
----------------------------------------------------------------------
   |                        OR
----------------------------------------------------------------------
    \Z                       before an optional \n, and the end of
                             the string
----------------------------------------------------------------------
  )                        end of grouping

Answer 2

您的代碼正確找到所有匹配項。 但是，由於每個查找都重新分配了seTab3Landmarks ，因此您只會在末尾打印出最后一個匹配項。

如果只希望第一個匹配，則應使用“ if”塊而不是“ while”塊（可找到所有匹配項）。