in reply to can I make my regex match first pattern instead of last?

Slurping files should generally be avoided, but your data seems to have a nice record separator so you can set $/ to that and then:

use strict;
use warnings;

my $item                  = "SeaMonkeys";
my $catNum                = "SMKY-1978";
my $remainingToReplace = 2;
my @lines;

local $/ = "\n\n";
while (defined (my $block = <DATA>)) {
    @lines = split "\n", $block;
    next unless $remainingToReplace;
    next unless $lines[0] =~ m/\Q$item\E/;

    # Replacement needed here
    print "***** Found $item, counter $remainingToReplace *****\n";
    --$remainingToReplace;

} continue {
    print join "\n", @lines, "\n";
}

__DATA__
Data per OP's node

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Prints:

    ELEMENT Kurt (Item := "BrightLite",
                  ItemID := 29,
                  CatalogNumber := "BTLT-9274",
                  Vendor := 100,
    END_ELEMENT

    ELEMENT Mick (Item := "PetRock",
                  ItemID := 36,
                  CatalogNumber := "PTRK-3475/A",
                  Vendor := 82,
    END_ELEMENT

***** Found SeaMonkeys, counter 2 *****
    ELEMENT Kurt (Item := "SeaMonkeys",
                  ItemID := 12,
                  CatalogNumber := "SMKY-1978/E",
                  Vendor := 77,
    END_ELEMENT

    ELEMENT Joe (Item := "Pong",
                 ItemID := 24,
                 CatalogNumber := "PONG-1482",
                 Vendor := 5,
    END_ELEMENT

***** Found SeaMonkeys, counter 1 *****
    ELEMENT Shane (Item := "SeaMonkeys",
                   ItemID := 1032,
                   CatalogNumber := "SMKY-1978/E",
                   Vendor := 77,
    END_ELEMENT

    ELEMENT Kurt (Item := "Battleship",
                  ItemID := 99,
                  CatalogNumber := "BTLS-5234",
                  Vendor := 529,
    END_ELEMENT

...

[download]
Perl reduces RSI - it saves typing

Replies are listed 'Best First'.
Re^2: can I make my regexp match first pattern instead of last?
by kleucht (Beadle) on Oct 25, 2008 at 18:55 UTC

    Awesome! Thanks for the answer! This seems to work fine. I had to modify your suggested regex a bit to handle matching both the item and the catalog number, since that was part of my original problem. I may not have made that very clear above.

    My regex looks like this, and it's acting on the whole $block variable instead of acting on just the first line of each block.

    m/ELEMENT\s(.+?)\s\(Item := \"\Q$item\E\".+?CatalogNumber := \"\Q$catNum\E/s

    Thanks again for the quick help!

[reply]
[d/l]
Re^2: can I make my regexp match first pattern instead of last?
by kleucht (Beadle) on Oct 25, 2008 at 19:47 UTC

    I have one small remaining problem, though. My data is already a large string variable instead of a filehandle. I used the filehandle in my example above because it was easy to just copy and paste. So what do I do with this "while" line in your solution if I already have the whole dataset slurped up into a variable called $fileContents?

    while (defined (my $block = <DATA>))
[reply]
[d/l]

      Use the string as a file:

      my $fileContents;

open my $scan, '<', \$fileContents;

while (defined (my $block = <$scan>)) {
    ...
}

close $scan;

      [download]
      Perl reduces RSI - it saves typing
[reply]
[d/l]
        It's working! Thanks for the help!
[reply]
        Using the string as a filehandle works fine. But now I get a runtime error that says "Can't use string ("") as a symbol ref while "strict refs" in use"

        on this line of code:

        open $ResultsHandle, '<', \$return;

        So how can I use strict, which is required by Perl Best Practices, and process a multi line string one line at a time?

        Thanks, Kurt

[reply]
[d/l]

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