Perl | keys() Function

keys() function in Perl returns all the keys of the HASH as a list. Order of elements in the List need not to be same always, but, it matches to the order returned by values and each function.

Syntax: keys(HASH)

Parameter:
HASH: Hash whose keys are to be printed

Return: For scalar context, it returns the number of keys in the hash whereas for List context it returns a list of keys.

Example 1:

#!/usr/bin/perl

%hash = ('Ten' => 10,
         'Eleven' => 11,
         'Twelve' => 12,
         'Thirteen' => 13);

@values = values( %hash );
print("Values are  ", join("-", @values), "\n");

@keys = keys( %hash );
print("Keys are ", join("-", @keys), "\n");

Output:

Values are  11-12-13-10
Keys are Eleven-Twelve-Thirteen-Ten

Example 2:

#!/usr/bin/perl

%hash = ('Geek' => 1,
         'For' => 2,
         'Geeks' => 3);

@values = values( %hash );
print("Values are  ", join("-", @values), "\n");

@keys = keys( %hash );
print("Keys are ", join("-", @keys), "\n");

Output:

Values are  3-2-1
Keys are Geeks-For-Geek