my @vals = ( 'cat', 'dog', 'mouse' );

##</code><code>##

  push( @vals, 'tiger' );
  print( join(',',@vals ) );

##</code><code>##

  print( pop( @vals ) );

##</code><code>##

  print( shift( @vals ) );

##</code><code>##

  print( join(',',@vals ) );