如何提取介于某个区间的几行文字，区间的开始和结束可以用正则表达式描述

infernor

刚把range  operator好好的看了一遍...

clfsy

原帖由 flw 于 2008-6-20 12:51 发表

向前断言，不匹配。

请教楼主，这边的？！是不是不匹配相应内容的意思？？？

还是有点理解不了，
(/$start/ .. /$end/) and !/$end/
从开始到结束，并且不包含结束，这本身不是矛盾吗？

我逻辑能力太差，能够请楼主简单举例说明！

呵呵！不好意思，弱弱的问题。

khandielas

再把这个顶出来

如果我想取出类似下面这样的怎么办
temp
testest
****SETTINGS****
test|/linux/bin
temp|/linux/etc
****SETTINGS****
testtestt
tmptmp
上下的标记都是一样的，所有range operator不行，有什么漂亮的招数么？

flw

to 楼上的，
range opreator 有两个版本：两个点的和三个点的。你用三个点就可以了。

khandielas

Beautiful, many thinks to FLW.

rainbowshine521

版主，能讲讲range opreator 吗？

nb509

Perl Range Operator
in a list context, this operator is easy to use and understand:  .. return a list of values counting (by ones) from the left value to the right value. This is useful for wrting for (1 .. 10) loops and for doing slice operations on arrays:

    @foo = @foo[-5 .. -1]; #slice last 5 items.
#!/usr/bin/perl
foreach (1..100)
{
   print;
}

foreach (A..B)
{
  print;
}
It is much more confusing in a scalar context. Let's look at the simplest cases first and then move to the more difficult:
#!/usr/bin/perl
while(<>)
{
   print "$. $_" if 3 .. 10;
}
That prints lines 3 to 10 of any input of file given to it. if we change it to print "$. $_" if 3 ... 10; it works the same way. But we aren't limited to line numbers. Let's create a file "g":
# stuff
# stuff
# end on same line as start
START foo  END
#
# end by itself
END
# more stuff
# more stuff
# another start
START
# and more stuff
END
# trailing stuff     


and a perl script to read it:
#!/usr/bin/perl

while(<>)
{
   print if(/START/../END/);
}
Running that against our file produces:
START foo  END
START
# and more stuff
END

But with the three dot version:
#!/usr/bin/perl

while(<>)
{
  print if(/START/.../END/);
}
the results are different:
START foo  END
#
# end by itself
END
START
# and more stuff
END

The difference is how the operator treats its left side and right side when they appear on the same line or out of order.Here's what's going on: with the two dot ".." version, the operator returns false until the left hand side is true. It then switches to returnning true and keeps doing that until its right hand expression evaluates to true. But the operator $EMAINS true until the next evaluation even so, so it only switches back to false when the next line is read. with the three dot "..." version, the right hand expression will not evaluated while the left hand is false, and vice versa. Confusing? you bet .. be very careful when using these opeartors and test your logic against sample input very carefully.



本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/emili/archive/2010/02/20/5312998.aspx

bluewaterray

我也来个，不要区间Start和end行的话
perl -ne '$in = 1 and next if /START/; $in = 0 and exit if /END/; print if $in'
要的话，稍微改下就是了。不过还是(/$start/ .. /$end/)简单些。。