Beefy Boxes and Bandwidth Generously Provided by pair Networks
P is for Practical
 
PerlMonks  

Answer: How do I extract all text between two keywords like start and end?

by chromatic (Archbishop)
on Apr 14, 2000 at 19:41 UTC ( #7636=categorized answer: print w/replies, xml ) Need Help??

Q&A > regular expressions > How do I extract all text between two keywords like start and end? - Answer contributed by chromatic

The basic regexp is:
if ($text =~ /\bstart\b(.*?)\bend\b/) { $result = $1; # do something with results }
Note that the . character matches any character but a newline (see m// if you want to span lines), the * means match zero or more times, and the ? forces * to match as few times as possible -- so it will pick up the first end instead of the last one. The \b is in there to prevent mismatches on words like 'starting' and 'backend'.

It has the limitation of not catching nested starts and ends, in which case you might go the recursion route, and write this as a function:

sub between { my $text = shift; if ($text =~ /start(.*?)end/) { $result = $1; between($result); } else { return $text; } }
That can become prohibitively expensive, depending on your data set. I suspect there's a more hideous solution involving split and join, but that's likely to be counterproductive at this point. It also depends on having balanced tags -- if you don't, don't do this!

Log In?
Username:
Password:

What's my password?
Create A New User
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others avoiding work at the Monastery: (1)
As of 2016-08-31 03:39 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    The best thing I ever won in a lottery was:















    Results (426 votes). Check out past polls.