title: How to print an array in upper case using tr///
body: <pre><code>my @array = qw( one two three four five six seven );
  my $arr = \@array;
  # $arr=~ tr/,(a-z)/\t(A-Z)/;
  print uc(join(' ', @array)), "\n";
  </code></pre>
  
  <p><strong>output</strong></p>
  
  <pre><code>ONE TWO THREE FOUR FIVE SIX SEVEN
  </code></pre>
  
  <p>But I want the same output using <code>tr///</code>.</p>