I agree that you need a flag to determine whether or not you are in a block, but beyond that, you need a datatype to hold all your data. I think you want an array of blocks that contains an array of lines that consists of an array of elements. This ought to do the trick: 
use Data::Dumper;

sub readFile{
    open my $fh, "resource/datafile.txt" || die "Cannot open: $!";
    @lines = <$fh>;
    $inblock = 0;
    my @block = [];shift @block;
    while($#lines >= 0){
        my $single = shift @lines;
        print $single;
        if($single =~ /END DATA/){
            $inblock = 0;
            push @allblocks,[@block];
            @block = [];shift @block;
        }
        push @block,[split ' ',$single] if $inblock;
        $inblock = 1 if($single =~ /START DATA/);
    }
}

readFile;
print Dumper(\@allblocks);

[download]
When a block starts the flag begins, and when a block ends the block is added to @allblocks. I don't consider myself a monk yet, but I tried the code and it works.

In reply to Re: Looking for a good way to split a file into equal sized arrays by TheForeigner
in thread Looking for a good way to split a file into equal sized arrays by Luken8r

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