@new_list = map {s/foo/bar/} @old_list;

##</code><code>##

    @new_list = map {s/foo/bar/; $_} @old_list;

##</code><code>##

  @transformed = map {s/$old/$new/} @raw; 

##</code><code>##

   $_ = $raw;
   $transformed = s/$old/$new/;