在 ASCII 图像中，例如：
....X....... ..X..X...X.... X.X...X..X..... X....XXXXXX..... X..XXX........... .....X.......... ..............X ..X...........X.... ..X...........X....X... ....X.....
我们'我想找到一个由三个 X 组成的简单垂直线结构，而不使用除正则表达式之外的最佳方法。
确定 PCRE/ 中是否存在这样的结构PHP、Perl、.NET 或类似的正则表达式，我们可以使用以下表达式：
(?xm) # ignore comments and whitespace, ^ matches beginning of line
^ # beginning of line
(?:
. # any character except \n
(?= # lookahead
.*+\n # go to next line
( ?+ . ) # add a character to the 1st capturing group
.*+\n # next line
( ?+ . ) # add a character to the 2nd capturing group
)
)*? # repeat as few times as needed
X .*+\n # X on the first line and advance to next line
?+ # if 1st capturing group is defined, use it, consuming exactly the same number of characters as on the first line
X .*+\n # X on the 2nd line and advance to next line
?+ # if 2st capturing group is defined, use it, consuming exactly the same number of characters as on the first line
X # X on the 3rd line简单匹配
For直接匹配并要求计数为匹配数，由于lookbehind支持有限，这个问题无法在PCRE或Perl中直接解决。
长度/间接解决方案
但是，如果答案被接受为匹配或替换的长度，然后可以用以下表达式回答：
^
(?:
(?: # match .+? characters
.
(?= # counting the same number on the following two lines
.*+\n
( ?+ . )
.*+\n
( ?+ . )
)
)+?
(?<= X ) # till the above consumes an X
(?= # that matches the following conditions
.*+\n
?+
(?<= X )
.*+\n
?+
(?<= X )
)
(?= # count the number of matches
.*+\n
( ?+ . ) # the number of matches = length of
)
)* # repeat as long as there are matches on this line
.*\n? # remove the rest of the line以上是您可以使用正则表达式在 ASCII 图像中找到由三个'X”组成的垂直线吗？的详细内容。更多信息请关注PHP中文网其他相关文章！
