my @users = qw( alice bob charlie );
my @ids   = qw( 123 456 789 );

my %id_of;
@id_of{@users} = @ids;  # hash slice


use Data::Dumper;
print Dumper(\%id_of);

##</code><code>##

$VAR1 = {
          'alice' => '123',
          'charlie' => '789',
          'bob' => '456'
        };