A two-pass process. First, count number of entries for each elem: 
  my %item_count;
  %item_count{$_}++ foreach (@array);

[download]
Next, remove any element whose item_count != 1: 
  @result = grep {$item_count{$_} == 1} @array;

[download]
--Dave.

Update: for the duplicate sub-pattern problem: 

  my %item_count;
  %item_count{$_}++ for grep {/pattern/} @array
  @result = grep {$item_count{$_} <= 1} @array;

[download]

Update 2: to avoid the uninitialized value warning: 

  @result = grep {($item_count{$_}||0) <= 1} @array;

[download]

In reply to Re: removing duplicated elements from array, with a difference by dpuu
in thread removing duplicated elements from array, with a difference by Anonymous Monk

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