in reply to File Parsing

This should work: 
#!/usr/bin/perl

use strict;
use warnings;

BJSFM_MS();


sub BJSFM_MS {
    my @temp;
    my $string1="FAILURE CRITERIA PER PLY";
    my $string2="AUTOMATIC SEARCH FOR FAILURE";
    while (my $line = <DATA>) {
        if ($line =~ /$string1/) {
            undef @temp;
            <DATA> for 1 .. 3;
            while (my $inner = <DATA>) {
                last if $inner =~ /^$/;
                push @temp, $inner;
            }
        }
    }
    use Data::Dumper;
    print Dumper \@temp;
}
__DATA__
                   FAILURE CRITERIA PER PLY

   DIST     ANGLE      PLY            FAILURE NUMBERS
                                   1         2       SHEAR
  0.000      0.00    -45.00     0.238     0.282    -1.459
  0.000      0.00      0.00     0.971     1.369     0.004
  0.000      5.00    -45.00     0.475     0.142    -1.585
  0.000      5.00      0.00     1.003     1.531    -0.274
  0.000     10.00    -45.00     0.721     0.037    -1.623

                   FAILURE CRITERIA PER PLY

   DIST     ANGLE      PLY            FAILURE NUMBERS
                                   1         2       SHEAR
  0.000      0.00    -45.00     0.247     0.293    -1.514
  0.000      0.00      0.00     1.008     1.422     0.004
  0.000      5.00    -45.00     0.493     0.147    -1.645
  0.000      5.00      0.00     1.042     1.589    -0.284

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You declare variables in a wider scope than needed. If you do not need the skipped lines, there is no reason to keep them in variables. Also, I do not see any benefit in using a hash if its keys are integers in the sequence 1, 2, 3, ...; I used an array instead. In your original do { ... } until, you would have needed something like until eof or $temp{$n-1} =~ /^$/.

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Re^2: File Parsing
by shortyfw06 (Beadle) on Jun 14, 2012 at 14:51 UTC

    The example in the original post is one step in my overall goal. In moving forward, I think I do want a hash, however, the hash value for key 1 should be @array. Then the @array is undefined and the next match creates a new @array with is then the hash value for key 2. This process is repeated until all matches have been found in the file for each element in @headers. I am really struggling with this one.... I hope my explanation is clear. Here is my attempt at this. 

    #!usr/bin/perl
use Tk;
use Cwd;
use strict;
use warnings;
#
######################################################################
+#####################
# GUI Building 
######################################################################
+#####################
#
# Create Main Window
my $mw=new MainWindow;
my $filename;
my $line;
my $n;
my @headers =     ("LAMINATE PROPERTIES",
        "LAMINATE STRESSES",
        "LAMINATE STRAINS",
        "CIRCUMFERENTIAL AND RADIAL STRESSES & STRAINS",
        "DISPLACEMENTS",
        "STRAINS PER PLY",
        "STRESSES PER PLY",
        "FAILURE CRITERIA PER PLY");
my $inner;
my @array;
my %hash;
my $ms_button = $mw->Button(-text=>"MS",
    -command=> \&BJSFM_MS)->pack();
MainLoop;

sub BJSFM_MS {
    $filename="BJSFM_out.prn";
    open(OUTPUT_FILE, "< $filename") or die "Can't find $filename!";
    $n=1;
        while ($line = <OUTPUT_FILE>) {
            if ($line =~ /$headers[$n-1]/) {
                undef @array;  #This clears the previous two instances
+ of $string1
                <OUTPUT_FILE> for 1..3;
                while ($inner = <OUTPUT_FILE>) {
                    last if $inner =~ /^$/;
                    push @array,$inner;
                }
                $hash{$n}=@array;
                $n++;
            }
        }
    close OUTPUT_FILE;
    print @array;
    print %hash;
}

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