open(DATA1,"<Switcher.properties");

open(DATA2,">FileWrite5.txt") ;


while(<DATA1>){

print DATA2 $_;

}

close(DATA1);
close(DATA2);

open(DATA1,"<Switcher.properties");

my @Lines=<DATA1>;


my %myHash; 
my @keys;
my @y;
my @values;
my $p=0;
my @i;
my @x;
my $k;

foreach my $val (@Lines)
{

#print "$val";

 @i=split('=',$val);

 $x=0;
@keys=@i[x]; 
@values =@i[$x+1]; 
print " Keys --> @keys    values  --> @values   \n";

@keys = @i[$x+2]; 

my $z= @i[$x];

print " The z value--> $z\n";

foreach my $val (@values) {

if($val=~m/,/){

 @y= split(',',$val); 
 $k=0;

foreach my $q (@y){

$myHash{$z}=$q ; 

print " The value of q --> $q  The key for that is --> @i[$x] \n \n ";
}

print "  Key  --> @i[$x]\n Multiple values for the key are --> @y ";

$k++;
}
}
$x++;
$p++; 

}

print " Hash values are as below \n";    
while ( my($key,$value)= each %myHash){

print "$key  :  $value\n " ; 

}
[download]

Please, use strict, use warnings, and format/indent your code properly. You'll save yourself a LOT of headaches that way.

Now, that said, a hash can by its very nature only contain one value for the same key. So simply assigning to the same key more than once won't work, as you'll just overwrite any old value that might previously have been associated with that key.

However, the value can be a reference to an array (or any data structure, really). perldsc has more information on this, but here's how I might do it:

#!/usr/bin/perl

use strict;
use warnings;
use feature qw/say/;

my %parsed = ();

while(<DATA>) {
    chomp;

    my ($key, $values) = split "=", $_, 2;
    my @values         = split ",", $values;

    $parsed{$key} = \@values;
}

foreach my $key (sort keys %parsed) {
    say "$key: ";

    foreach my $value (@{ $parsed{$key} }) {
        say "\t$value";
    }
}

__DATA__
key1=value1
key2=value2,value3,value4,value4,value5,value6,value7,value8,value9,va
+lue10
key3=value11,value12
[download]

This outputs:

$ perl 1119309.pl
key1:
        value1
key2:
        value2
        value3
        value4
        value4
        value5
        value6
        value7
        value8
        value9
        value10
key3:
        value11
        value12
$
[download]

The crucial lines here are the following two:

    $parsed{$key} = \@values;

    # ...

    foreach my $value (@{ $parsed{$key} }) {
[download]

The first of these takes a reference to @values (using the \ operator); the second takes the reference stored in $parsed{$key} and dereferences it, i.e. converts it back to to an array, by using the @{ ... } circumfix construct. (Since @ is the array sigil, this can mnemonically be thought of as encapsulating a certain something and presenting it as an array on the outside.)

I hope this'll get you started! If you have further questions, just ask.