Remove duplicate elements

Remove duplicate elements
You are encouraged to solve this task according to the task description, using any language you may know.

Given an Array, derive an Array containing only the unique elements; that is, derive an array in which all duplicate elements are removed.

AppleScript

set array to {1, 2, 3, "a", "b", "c", 2, 3, 4, "b", "c", "d"}
set unique to {}
repeat with i in array
    -- very important -- list index starts at 1 not 0
    if (i is not in unique) then
        set unique to unique & i
    end if
end repeat

C++

#include <set>
#include <iostream>
using namespace std;

int main( int argc, char* argv[] ) {
    typedef set<int> TyHash;
    int data[] = {1, 2, 3, 2, 3, 4};

    TyHash hash(data, data + 6);

    cout << "Set items:" << endl;
    for (TyHash::iterator iter = hash.begin(); iter != hash.end(); iter++)
          cout << *iter << " ";
    cout << endl;
}

C#

Compiler: MSVS 2005

 List<int> nums = new List<int>( new int { 1, 1, 2, 3, 4, 4 } );
 List<int> unique = new List<int>();
 foreach( int i in nums )
   if( !unique.Contains( i ) )
     unique.Add( i );

D

void main() {
    int[] data = [1, 2, 3, 2, 3, 4];
    int[int] hash;
    foreach(el; data)
        hash[el] = 0;
}

Haskell

import List

values = [1,2,3,2,3,4]
unique = nub values

IDL

 result = uniq( array[sort( array )] )

Java

 //Using Java 1.5/5.0
 Object[] data = new Object[] {1, 2, 3, "a", "b", "c", 2, 3, 4, "b", "c", "d"};
 Set uniqueSet = new HashSet(Arrays.asList(data));
 Object[] unique = uniqueSet.toArray();

Perl

Interpeter: Perl

my %hash;
my @list = (1, 2, 3, 'a', 'b', 'c', 2, 3, 4, 'b', 'c', 'd');
@hash{@list} = 1;
# the keys of %hash now contain the unique list
my @unique_list = keys(%hash);

PHP

 $list = array(1, 2, 3, 'a', 'b', 'c', 2, 3, 4, 'b', 'c', 'd');
 $unique_list = array_unique($list);

Python

 data = [1, 2, 3, 'a', 'b', 'c', 2, 3, 4, 'b', 'c', 'd']

Using sets

 unique = list(set(data))

See also http://www.peterbe.com/plog/uniqifiers-benchmark and http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52560

Ruby

 ary = [1,1,2,1,'redundant',[1,2,3],[1,2,3],'redundant']
 uniq_ary = ary.uniq
 # => [1, 2, "redundant", [1, 2, 3]]

TCL

 set result [lsort -unique $arrayname]