Regex for simple parsing job

toadi has asked for the wisdom of the Perl Monks concerning the following question:

Hi,

I program perl for a while now and still suck at regexes.

My file looks like:

STARTP
TITLE
some gibberish
some more gibberish
ENDTITLE
TITLE
some gibberish
some more gibberish
ENDTITLE
TITLE
some gibberish
some more gibberish
ENDTITLE
ENDP
STARTP
TITLE
some gibberish
some more gibberish
ENDTITLE
TITLE
some gibberish
some more gibberish
ENDTITLE
TITLE
some gibberish
some more gibberish
ENDTITLE
ENDP
[download]

I read following link: "How do I extract all text between two keywords like start and end?". But it didn't make me any wiser.

I want to get everyting from STARTP until ENDP. En then cut stuff up between TITLE and ENDTITLE. But if I do like the suggested link I get everything fron first STARTP until last ENNDP. And I want to match first from First STARTP until first ENDP in the file and then from next STARTP until next ENDP. And the same for TITLE and ENDTITLE.

And no there is no recursion in these tags.

thanx

--
My opinions may have changed,
but not the fact that I am right

_{janitored by ybiC: Retitle from one-word "regex" nodetitle to avoid hindering site searching. Also converted node link from <a href...> to Monastery style [id://nnnn] to avoid logging out monks with cookie set from different PM domain (perlmonks.(org|net), sans leading "www"...)}

Comment on Regex for simple parsing job Download Code

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Re: Regex for simple parsing job by pbeckingham (Parson) on Jul 27, 2004 at 12:26 UTC
Wow, a perfect use of the scalar range operator. #! /usr/bin/perl -w use strict; my @titles; while (<DATA>) { if (my $num = /TITLE/ .. /ENDTITLE/) { push @titles, $_ unless $num == 1 \|\| $num =~ /E/; } } print for @titles; __DATA__ STARTP TITLE some gibberish some more gibberish ENDTITLE TITLE some gibberish some more gibberish ENDTITLE TITLE some gibberish some more gibberish ENDTITLE ENDP STARTP TITLE some gibberish some more gibberish ENDTITLE TITLE some gibberish some more gibberish ENDTITLE TITLE some gibberish some more gibberish ENDTITLE ENDP [download]	[reply] [d/l]
Re^2: Regex for simple parsing job by Art_XIV (Hermit) on Jul 27, 2004 at 13:24 UTC
Although I like a spicy regex as much as the next guy, I think that the use of the flip-flop operator, as pointed out by pbeckingham and diebyz is much more elegant and (probably) more efficient, since it allows you to avoid slurping the file that is being parsed. The 'scalar range' / 'flip-flop' operator is one of the sweetest pieces of syntactical sugar that Perl offers, if you ask me. Hanlon's Razor - "Never attribute to malice that which can be adequately explained by stupidity"	[reply]
Re^3: Regex for simple parsing job by toadi (Chaplain) on Jul 27, 2004 at 13:45 UTC
For the first Part From STARTP to ENDP. But as I stated previous not for the TITLE part, because there is no endtag. But I'm going to use the flip flop operator because the file can be very large. Thanx for pointing me to this!!! -- My opinions may have changed, but not the fact that I am right	[reply]
Re: Regex for simple parsing job by davorg (Chancellor) on Jul 27, 2004 at 09:23 UTC
Would have been nice to see you code so we could show you where you are going wrong. But this seems to do what you want. #!/usr/bin/perl use strict; use warnings; my $data = do { local $/; <DATA> }; my @data = $data =~ /STARTP(.?)ENDP/sg; foreach (@data) { my @titles = /TITLE(.?)ENDTITLE/sg; $_ = \@titles; } foreach my $i (0 .. $#data) { print "Block $i\n"; foreach my $j (0 .. $#{$data[$i]}) { print "Title $j:\n$data[$i][$j]\n"; } print "\n"; } __DATA__ STARTP TITLE some gibberish some more gibberish ENDTITLE TITLE some gibberish some more gibberish ENDTITLE TITLE some gibberish some more gibberish ENDTITLE ENDP STARTP TITLE some gibberish some more gibberish ENDTITLE TITLE some gibberish some more gibberish ENDTITLE TITLE some gibberish some more gibberish ENDTITLE ENDP [download] -- <http://www.dave.org.uk> "The first rule of Perl club is you do not talk about Perl club." -- Chip Salzenberg	[reply] [d/l]
Re^2: Regex for simple parsing job by toadi (Chaplain) on Jul 27, 2004 at 09:39 UTC
actually I was still looking for the `/sg` switch in the regex. That's why my code didn't match anything. But thanx for helping. -- My opinions may have changed, but not the fact that I am right	[reply] [d/l]
Re^2: Regex for simple parsing job by toadi (Chaplain) on Jul 27, 2004 at 09:53 UTC
In the file I don't have ENDTITLE ass ending but just TITLE until next TITLE until next TITLE. How do I match that? Update Seems split does the job :) -- My opinions may have changed, but not the fact that I am right	[reply]
Re^3: Regex for simple parsing job by davorg (Chancellor) on Jul 27, 2004 at 10:10 UTC
Won't "split" give you an extra empty title? I fixed the second regex like this: `my @titles = /TITLE(.?)(?=TITLE\|$)/sg;` [download] Update:* regex re-fixed -- <http://www.dave.org.uk> "The first rule of Perl club is you do not talk about Perl club." -- Chip Salzenberg	[reply] [d/l]
Re^4: regex by toadi (Chaplain) on Jul 27, 2004 at 10:39 UTC
Re: Regex for simple parsing job by ccn (Vicar) on Jul 27, 2004 at 09:17 UTC
my $str = <<TEXT; STARTP TITLE some gibberish some more gibberish ENDTITLE TITLE some gibberish some more gibberish ENDTITLE TITLE some gibberish some more gibberish ENDTITLE ENDP STARTP TITLE some gibberish some more gibberish ENDTITLE TITLE some gibberish some more gibberish ENDTITLE TITLE some gibberish some more gibberish ENDTITLE ENDP TEXT my @ary; foreach my $p ($str =~ /^STARTP\n(.?)ENDP/msg) { my @p; foreach my $t ($p =~ /^TITLE\n(.?)ENDTITLE/msg) { push @p, $t; } push @ary, \@p; } use Data::Dumper; print Dumper(\@ary); [download] `$VAR1 = [ [ 'some gibberish some more gibberish ', 'some gibberish some more gibberish ', 'some gibberish some more gibberish ' ], [ 'some gibberish some more gibberish ', 'some gibberish some more gibberish ', 'some gibberish some more gibberish ' ] ];` [download] update: a little bug fixed, 'm' modifier added to second regexp, thanks to guha	[reply] [d/l] [select]
Re: Regex for simple parsing job by deibyz (Hermit) on Jul 27, 2004 at 11:26 UTC
You can have a look at this node.	[reply]
Re: Regex for simple parsing job by Anonymous Monk on Jul 27, 2004 at 09:21 UTC
`$_ = "STARTP ... ENDP"; @data = map {[/^TITLE\n([^E](?:E(?!NDTITLE)[^E]))ENDTITLE/gm]} /^ST +ARTP\n([^E](?:E(?!NDP)[^E]))ENDP/gm;` [download]	[reply] [d/l]