Parsing file to pull out sections of text

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

Hi all, What I am trying to do is parse through a file formatted like below.
I want to go through the data, search for "d1", and take all of the data between "d1" and "d4" (inclusive) and place it in an array to do something interesting with later.
In the interest of brevity, I'll leave out the sordid details of what I've tried (although I'd be more than happy to provide it if it's helpful), but I keep getting stuck on how exactly to trigger getting a chunk of the file, and once finding the end trigger, to keep going through the rest of the file.
Thanks for any pointers :-)
source file (yes the source would have data separated by returns):

a
b
c
d
d1
d2
d3
d4
a
b
d1
d2
d4
a
f
g
...
[download]

Comment on Parsing file to pull out sections of text Download Code

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Re: Parsing file to pull out sections of text by toolic (Bishop) on Feb 03, 2009 at 18:05 UTC
One way is to use Range Operators: `use strict; use warnings; while (<DATA>) { print if (/d1/ .. /d4/); } __DATA__ a b c d d1 d2 d3 d4 a b d1 d2 d4 a f g` [download] prints: `d1 d2 d3 d4 d1 d2 d4` [download]	[reply] [d/l] [select]
Re: Parsing file to pull out sections of text by DStaal (Chaplain) on Feb 03, 2009 at 17:46 UTC
What have you tried? This looks like something fairly simple... Basically, I'd set a flag when I see d1, and unset it when I see d4. While the flag is set, push to the array. That's about three lines of code...	[reply]
Re: Parsing file to pull out sections of text by artist (Parson) on Feb 03, 2009 at 20:46 UTC
`use strict; use warnings; my $flag = 0; my $start = 'd1'; my $end = 'd4'; my @array; while (<DATA>) { chomp; if(/$start/){ $flag = 1; @array = (); } elsif(/$end/) { $flag = 0; print "@array\n"; } else{ push @array, $_ if $flag; } }` [download] --Artist	[reply] [d/l]
Re: Parsing file to pull out sections of text by kennethk (Abbot) on Feb 03, 2009 at 17:43 UTC
Sounds like a job for Perl regular expressions. `while (<>) { if (/(d\d)/) { push @array, $1; } }` [download]	[reply] [d/l]


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