push @client_list,
    Client::Data::->new(name => $name, address => $addr, city => $city);

##</code><code>##

my $wanted_client = 'Mary Smith';

##</code><code>##

for my $client (@client_data) {
    if ($client->name eq $wanted_client) {
        print "${wanted_client}'s city is ", $client->city;
        last;
    }
}

##</code><code>##

print "${wanted_client}'s city is ", $client_data_for{$wanted_client}->city;