java - 正则表达式提取最后一次出现后的行

Question

嗨，我有一个这样的段落:

            output 123

            Deepak everywhere
            Deepak where are

            output 123

            Ankur Everywhere
            Deepak where are

            last

            Deepak everywhere
            Deepak where are

我想在最后一次出现“output 123”之后提取到“last”。这就是我所期望的:

            Ankur Everywhere
            Deepak where are

            last

我使用这个正则表达式模式 - (?<=(output))([^\\n]*)last 。但使用这个，我得到的是:

            output 123

            Deepak everywhere
            Deepak where are

            output 123

            Ankur Everywhere
            Deepak where are

            last

有人可以帮忙吗？我使用这个工具 - http://regexr.com?360ek

Answer 1

您可以使用此模式并提取第一个捕获组:

output\\b[^\\n]*\\s*((?>[^o\\s]++|\\s++(?!last\\b)|o(?!utput\\b))++)(?=\\s+last\b)

详情:

output\\b[^\\n]*\\s* # the begining (exclude from the final result
                     # but used as an anchor)
(                         # open the capturing group
    (?>                   # open an atomic group (all the possible content)
        [^o\\s]++         # all that is not a "o" or a white character
      |                   # OR
        \\s++(?!last\\b)  # white characters but not followed by "last"
                          # (here the possessive quantifier is needed to forbid
                          # backtracks)
      |                   # OR
        o(?!utput\\b)     # "o" not followed by "utput\b"
    )++                   # repeat the atomic group one or more times
)                         # close the capturing group
(?=\\s+last\b)            # followed by white characters and "last"

您可以通过以下方式找到捕获组的内容:m.group(1)