Hi, In your code if the first array element is matched with second array means you need to break the inner loop and need to process the next element from the first array.

When the first array element is matched with the second array element you are setting the $found=1 and the first array element again checked with the other elements of second array, So if not matched $found=0 So when the $found is 1 printing matched, when it is 0 it prints not matched.

Try this code:

use strict;
use warnings;
use utf8;

my $found;
my @array =    ("54321","54312","5999","54352","12345");

  my @original =("12345","54321","12355");

    foreach my $string(@array)
    {
        foreach my $string2(@original)
        {
            if ($string eq $string2) {
                $found = 1;
                last;
            }
            else
            {
                $found = 0;
            }

        }

        if ($found == 0) {
        print "$string not found\n";
        }
        else
        {
        print "$string found\n";
        }
}
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Update:

<p>Example:</p>
use strict;
use warnings;
use Data::Dumper;
use Array::Utils qw(:all);

my @a = qw( a b c d );
my @b = qw( c d e f );

my @diff = array_diff(@a, @b);

print "Difference:\n";
print Dumper \@diff;

print "Intersection:\n";
my @isect = intersect(@a, @b);
print Dumper \@isect;

print "Unique union:\n";
my @unique = unique(@a, @b);
print Dumper \@unique;

# check if arrays contain same members
if ( !array_diff(@a, @b) ) {
# do something
}

# get items from array @a that are not in array @b
my @minus = array_minus( @a, @b );

print Dumper \@minus;
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Ah awesome, you guys rock! Don't know how I did not think of doing that. Thanks a million guys! Once last question. In some instances the file will have an entry twice in the original array .how can I match to print the string once but also print that I found it twice. for instance found 12345 (2 matches)

Use the code below to say matched element count also, this will tell you the possible matches not only twice.

 
use strict;
use warnings;
use Data::Dumper;

my %hash_count;
my @array =  ( "54321", "54312" ,    "5999" ,    "54352" ,    "12345" 
+   );

  my @original =    ( "12345" ,    "54321" ,    "12355", "54321"    );

    foreach my $string(@array)
    {
        foreach my $string2(@original)
        {
            if ($string eq $string2) {
                $hash_count{$string}++;
            }
            else
            {
                unless (exists $hash_count{$string})
                {
                    $hash_count{$string} = 0;
                }
            }

        }
    }

print Dumper \%hash_count;

foreach (keys %hash_count)
{        
    unless ($hash_count{$_}) {
            print "$_ Not found\n";
    }   
    else
    {   
            print "$_ found $hash_count{$_} times\n" ;
    }
}
[download]

Track counts instead of assign 1 to hash:

use strict   ;
use warnings ;


my @array    = ( "54321", "54312", "5999", "54352", "12345" ) ;
my @original = ( "12345" , "54321" , "12345"       ) ;

my %count ;
map( { $count{ $_ }++ } @original );

print "". ( ( $count{ $_ } ) ? "$_ Found $count{ $_ } times.\n" : "$_ 
+Not Found\n" ) foreach ( @array ) ;
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Output:

54321 Found 1 times.
54312 Not Found
5999 Not Found
54352 Not Found
12345 Found 2 times.
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Change loop to:

foreach $string(@array) {
    
    my $found = 0 ;
    foreach $string2(@original) {
    if ($string eq $string2) {
        $found = 1;
    }
    }

    if ($found == 0) {
    print "$string not found\n";
    }
    else
    {
    
    print "$string found\n";
    
    }
    
}
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Also use strict and warnings ...

More importantly its more efficient if you use a hash:

use strict   ;
use warnings ;

my @array    = ( "54321", "54312", "5999", "54352", "12345" ) ;
my @original = ( "12345" , "54321" , "12355"                ) ;

my %hash  = map( { ( $_ => 1 ) } @original ) ;
print "". ( ( $hash{ $_ } ) ? "$_ Found\n" : "$_ Not Found\n" ) foreac
+h ( @array ) ;
[download]

Checkk the FAQ. Refer: perldoc -q intersection for the use of a hash in comparing arrays.