regex - 仅当它们在特定字符串之间时，如何在正则表达式中查找匹配项？

Question

我试图在文本的特定位置找到多个匹配项。
例如，在下面的文本中，我想找到所有 a=.*;之间abcd和 xyz

abcd
a=1;
some text
a=2; some text
b=3;
a=4;
xyz
a=5;
a=6;

所以它应该只匹配:

 a=1;   
 a=2;
 a=4;

并且不匹配:

a=5;
a=6;

到目前为止，我尝试了以下正则表达式:

(?<=abcd\n)(.*)(?=\nxyz) 

返回 'abcd' 之间的字符串和 'xyz' ,但我没有成功匹配所有 a=.*;里面

Answer 1

用

(?<=abcd[\s\S]*)a=.*;(?=[\s\S]*xyz)

见 JS regex proof .
说明

--------------------------------------------------------------------------------
  (?<=                     look behind to see if there is:
--------------------------------------------------------------------------------
    abcd                     'abcd'
--------------------------------------------------------------------------------
    [\s\S]*                  any character of: whitespace (\n, \r,
                             \t, \f, and " "), non-whitespace (all
                             but \n, \r, \t, \f, and " ") (0 or more
                             times (matching the most amount
                             possible))
--------------------------------------------------------------------------------
  )                        end of look-behind
--------------------------------------------------------------------------------
  a=                       'a='
--------------------------------------------------------------------------------
  .*                       any character except \n (0 or more times
                           (matching the most amount possible))
--------------------------------------------------------------------------------
  ;                        ';'
--------------------------------------------------------------------------------
  (?=                      look ahead to see if there is:
--------------------------------------------------------------------------------
    [\s\S]*                  any character of: whitespace (\n, \r,
                             \t, \f, and " "), non-whitespace (all
                             but \n, \r, \t, \f, and " ") (0 or more
                             times (matching the most amount
                             possible))
--------------------------------------------------------------------------------
    xyz                      'xyz'
--------------------------------------------------------------------------------
  )                        end of look-ahead