Remove repetitions in Array

The normal idea is to have an hash table, iterate over the array and using the elements as keys.

Something like :

Code:

my @array = (1,5,3,7,9,1,4,5,7,6,7);

my %hash;

foreach my $element (@array) {
	$hash{$element}++
}

my @arrayNoRep = keys %hash;
print join(", ", @arrayNoRep);

Lets simplify the loop

Code:

my @array = (1,5,3,7,9,1,4,5,7,6,7);

my %hash;
$hash{$_}++ foreach @array;

my @arrayNoRep = keys %hash;
print join(", ", @arrayNoRep);

But do we need the loop?

Code:

my @array = (1,5,3,7,9,1,4,5,7,6,7);

my %hash;
@hash{@array} = ();

my @arrayNoRep = keys %hash;
print join(", ", @arrayNoRep);

And throwing away the hash defeniton.

Code:

my @array = (1,5,3,7,9,1,4,5,7,6,7);

my @arrayNoRep = keys %{{map {$_=>0} @array}};

print join(", ", @arrayNoRep);

I love this one line in Perl.

 

That's really cool!

 

This post has become a Recipe at my new Perl website.

http://sites.google.com/site/oleber...-arrays/01-getting-a-duplication-free-array-1

 

Remove repetitions in Array without loop

Code:

my @array = (1,5,3,7,9,1,4,5,7,6,7);
@t{@array}=();
print join sort keys %t,",";

Result : 1, 3, 4, 5, 6, 7, 9

 

So, What did you add to the subject msmani_1980?

 

I couldn't get this line in the 3rd code block
@hash{@array} = ();

hash is defined with % in the previous line (%hash) and then it is seen with @ which is meant for array. Can somebody explain me, what exactly "@", prepended to hashname, does?

 

"@", prepended to hashname means we are accessing a hash slice i.e. a group of elements instead of one element a time.