Odd number of elements in hash assignment at ...

##</code><code>##

use strict;
use warnings;

my $obj = bless do { \my $x }, __PACKAGE__; # current package, e.g. 'main'

print "wrong:\n";

$obj->wrong(name =>'John', age => 28);

print "-" x 50, "\n";
print "right:\n";

$obj->right(name =>'Paul', age => 30);

sub wrong {
    warn +(caller(0))[3],'(',join(',',map "'$_'", @_),")\n";
    my %h = @_;
    print "$_ => $h{$_}\n" for keys %h;
}

sub right {
    warn +(caller(0))[3],'(',join(',',map "'$_'", @_),")\n";
    my $self = shift;
    my %h = @_;
    print "$_ => $h{$_}\n" for keys %h;
}
__END__
wrong:
main::wrong('main=SCALAR(0x8167870)','name','John','age','28')
Odd number of elements in hash assignment at - line 17.
Use of uninitialized value in concatenation (.) or string at - line 18.
28 => 
John => age
main=SCALAR(0x8167870) => name
--------------------------------------------------
right:
main::right('main=SCALAR(0x8167870)','name','Paul','age','30')
name => Paul
age => 30

##</code><code>##

if(!$data{$match})
     {
        $data{$match}++;
        $count = $count + 1;
     }