Best Way to Check Uniqueness in Array

[Kasp]

Hello,

Consider an unsorted array
my @array = ( 2, 4, 6, 4, 2, 6, A, B, C, C, B, A);

Now, I wish to remove the duplicate elements from this array. A good way may
be to assign these array's elements as keys of a hash. And then convert the
keys back to the array like this:
<UNTEST CODE>

my @array = ( 2, 4, 6, 4, 2, 6, A, B, C, C, B, A);
my %hash = ();
for($i=0;$i<=$#array;$i++){
$hash{ $array[$i] } = '';
}

(@array) = (keys %hash); # @array now contains unique elements
</UNTEST CODE>

Is there a better or shorter way?

Thanks.
--

 

[Jürgen Exner]

Consider an unsorted array
my @array = ( 2, 4, 6, 4, 2, 6, A, B, C, C, B, A);

Now, I wish to remove the duplicate elements from this array.

This has been discussed a few times before, please see "perldoc -q
duplicate" or http://www.badtz.org/pics/bart.gif

jue

 

[Andreas Kahari]

Hello,

Consider an unsorted array
my @array = ( 2, 4, 6, 4, 2, 6, A, B, C, C, B, A);

Now, I wish to remove the duplicate elements from this array. A good way may
be to assign these array's elements as keys of a hash. And then convert the
keys back to the array like this:
<UNTEST CODE>

[cut]

my @array = qw( 2 4 6 4 2 6 A B C C B A );
my %hash;

@hash{@array} = 1;
@array = keys %hash;

 

[Anno Siegel]

Hello,

Consider an unsorted array
my @array = ( 2, 4, 6, 4, 2, 6, A, B, C, C, B, A);

Now, I wish to remove the duplicate elements from this array. A good way may
be to assign these array's elements as keys of a hash. And then convert the
keys back to the array like this:
<UNTEST CODE>

[cut]

my @array = qw( 2 4 6 4 2 6 A B C C B A );
my %hash;

@hash{@array} = 1;

Why assign 1 to the hash slice, that's neither here nor there. Either
leave all values undefined:

@hash{@array} = ();

or set them all to 1:

@hash{@array} = (1) x @array;

or

%hash = map { ( $_, 1) } @array;

@array = keys %hash;

Mind you, your code works, but assigning 1 to one key and leaving the
others undefined makes no sense.

Anno

 

[Kasp]

This has been discussed a few times before, please see "perldoc -q

duplicate" or http://www.badtz.org/pics/bart.gif

Sorry, didn't do my homework

 

[Andreas Kahari]

Why assign 1 to the hash slice, that's neither here nor there. Either
leave all values undefined:

@hash{@array} = ();

Yes, that makes more sense.