in reply to Help with getting everything from X until Y

In addition to the other answers here which offer regular expressions and alternate line break characters which match over multiple lines, you may want to consider the use of the .. range operator:

#!/usr/bin/perl

while ( <DATA> ) {
   print if /<b>/ .. /<br>/;
}

__DATA__
a whole
lot of  worthless
stuff
<b>Title:
</b>
STRING_I_WANT<br>
more worthless
meaningless stuff
or sometimes
<b>Title:
</b>ANOTHER STRING_I_WANT<br>

[download]

And the resultant output ...

/users/rc6286 > perl test.perl
<b>Title:
</b>
STRING_I_WANT<br>
<b>Title:
</b>ANOTHER STRING_I_WANT<br>

[download]

Alternatively, if you are ensure that the match is made across multiple lines, and not merely against a single line which may contain the requisite start and stop range elements, the ... range operator may be used which does not test the second operand in the range statement until the next iteration, thereby ensuring that multiple lines are matched. See the perlop man page under the heading "Range Operators" for further details.

 

perl -le 'print+unpack"N",pack"B32","00000000000000000000001001100001"'

Replies are listed 'Best First'.
Re: Re: Help with getting everything from X until Y
by Anonymous Monk on May 29, 2003 at 05:16 UTC
    Thanks gents - these are all quite useful. I tamed-down the HTML a bit in my original post. It was actually a bit uglier. Here's my results w/ the 3 examples: 
    local $/ = "<br>";
while ( <DATA> ) {
   print $1 if /Title:(.*?)<br>/s;
}

    [download]
    This works nice, but I got a lot of white spaces. Also, for some reason, I was getting an extra <\\b> in addition to the STRING_I_WANT. Easy to take out, but seem my question at the bottom if you could. #2: 
    $whole_file =~ /Title:.*?</b>(.*?)<br>/ms;

    [download]
    I actually assumed this would be the easiest way. I tried: 
    undef $/;
chomp($whole_file = <IN>);
$whole_file =~ s/.*?Title:.*?<\/b>(.*?)<br>/$1/ ;
print "$whole_file";

    [download]
    The only thing this got me was the whole file printed out. :(

    #3 
    while ( <DATA> ) {
   print if /<b>/ .. /<br>/;
}

    [download]
    This worked well. It would print out the whole line if it found something that fit in the range description. But I'm curiuos on one thing on this and the first example - how would I put the value into a variable when using the 
    print if /<b>/ .. /<br>/;

    [download]
    Thanks for your help. I'm making some progress but I'm still "in the books", so there's quiet a few tricks I've still yet to learn.
[reply]
[d/l]
[select]
      When the while is written in this manner, each line that is processed is assigned to the default perl variable, $_ - When subsequent matching and printing is performed without specifying a variable or specific string to act upon, the use of the default variable $_ is assumed and it is this which is acted upon.

      See the perlvar and perlop man pages for further detail.

       

      perl -le 'print+unpack"N",pack"B32","00000000000000000000001001100010"'

[reply]
[d/l]
[select]
      Modifiers matter. And didn't you say there was more than one occurrence in this file? Here's an untested example:

      undef $/;
chomp($whole_file = <IN>);
while ($whole_file =~ /Title:.*?<\/b>(.*?)<br>/sg) {
  print $1 . "\n";
}

      [download]
[reply]
[d/l]

        Just for the sake of scientific experiment I tested it and it works ... sort of.

        As there is an end-of-line in front of the first 'STRING_I_WANT' and no end-of-line characters after it or around the 'ANOTHER STRING_I_WANT', the result looks rather odd, difficult to read and (almost) impossible to use in a meaningful way.

        If you want to further use the result, it seems better to put some 'start' and 'stop' markers around the results: 

        use strict;
use warnings;

undef $/;
chomp(my $whole_file = <DATA>);
print "***\n$whole_file\n***\n";
$whole_file =~ s/.*?Title:.*?<\/b>\s?(.*?)<br>/<WANTED>$1<\/WANTED>\n/
+gs ;
print "$whole_file";


__DATA__
a whole
lot of  worthless
stuff
<b>Title:
</b>
STRING_I_WANT<br>
more worthless
meaningless stuff
or sometimes
<b>Title:
</b>ANOTHER STRING_I_WANT<br>

        [download]

        CountZero

        "If you have four groups working on a compiler, you'll get a 4-pass compiler." - Conway's Law

[reply]
[d/l]

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