Sets

Note

Before version 3.0.0-alpha.13, sets were simply arrays that deduplicated their items. To emulate the former behaviour, add the clause VALUE $value.distinct() to a DEFINE FIELD definition.

A set is similar to an array, but with two key differences:

• The values in a set are automatically deduplicated.
• The values in a set are automatically ordered.

A set can be created using the literal syntax {}.

RETURN {1, 6, 6, 2};
-- {1, 2, 6}

To create a set with zero items or a single item, add a comma.

{,}.is_set();  -- true
{9,}.is_set(); -- true

{}.is_set();   -- false
{9}.is_set();  -- false

In addition to the {} literal syntax, an array can be cast into a set.

DEFINE FIELD bank_accounts ON TABLE customer TYPE array<int>;
DEFINE FIELD languages ON TABLE customer TYPE set<string>;

CREATE customer SET
    bank_accounts = [
      55555,
      55555,
      98787
    ],
    languages = <set>[
        "en",
        "ja",
        "kr",
        "kr"
    ];

Output
[
	{
		bank_accounts: [
			55555,
			98787
		],
		id: customer:uv6mn62t8td9vzvfogh4,
		languages: {
			'en',
			'ja',
			'kr'
		}
	}
]

Casting into a set and back into an array can be a convenient way to deduplicate items in the same way that the array::distinct() and array::sort() functions are used.

<array><set>[18,7,6,6,6,6,5,4,3,9];
[18,7,6,6,6,6,5,4,3,9].distinct().sort();

Output
[3, 4, 5, 6, 7, 9, 18]