Functions for dictionaries

DictCreate

Construct an empty dictionary. Two arguments are passed: for a key and a value. Each argument specifies a string with the data type declaration or the type itself built by type functions. There are no dictionaries with an unknown key or value type in YQL. As a key, you can set a primitive data type, except for Yson and Json that may be optional or a tuple of them of a length of at least two.

Documentation for the type definition format.

Examples

SELECT DictCreate(String, Tuple<String,Double?>);

SELECT DictCreate(Tuple<Int32?,String>, OptionalType(DataType("String")));

SetCreate

Construct an empty set. An argument is passed: the key type that can be built by type functions. There are no sets with an unknown key type in YQL. As a key, you can set a primitive data type, except for Yson and Json that may be optional or a tuple of them of a length of at least two.

Documentation for the type definition format.

Examples

SELECT SetCreate(String);

SELECT SetCreate(Tuple<Int32?,String>);

DictLength

The count of items in the dictionary.

Examples

SELECT DictLength(AsDict(AsTuple(1, AsList("foo", "bar"))));

DictHasItems

Check that the dictionary contains at least one item.

Examples

SELECT DictHasItems(AsDict(AsTuple(1, AsList("foo", "bar")))) FROM my_table;

DictItems

Get dictionary contents as a list of tuples including key-value pairs (List<Tuplekey_type,value_type>).

Examples

SELECT DictItems(AsDict(AsTuple(1, AsList("foo", "bar"))));
-- [ ( 1, [ "foo", "bar" ] ) ]

DictKeys

Get a list of dictionary keys.

Examples

SELECT DictKeys(AsDict(AsTuple(1, AsList("foo", "bar"))));
-- [ 1 ]

DictPayloads

Get a list of dictionary values.

Examples

SELECT DictPayloads(AsDict(AsTuple(1, AsList("foo", "bar"))));
-- [ [ "foo", "bar" ] ]

DictLookup

Get a dictionary element by its key.

Examples

SELECT DictLookup(AsDict(
    AsTuple(1, AsList("foo", "bar")),
    AsTuple(2, AsList("bar", "baz"))
), 1);
-- [ "foo", "bar" ]

DictContains

Checking if an element in the dictionary using its key. Returns true or false.

Examples

SELECT DictContains(AsDict(
    AsTuple(1, AsList("foo", "bar")),
    AsTuple(2, AsList("bar", "baz"))
), 42);
-- false

DictAggregate

Apply aggregation factory to the passed dictionary where each value is a list. The factory is applied separately inside each key.
If the list is empty, the aggregation result is the same as for an empty table: 0 for the COUNT function and NULL for other functions.
If the list under a certain key is empty in the passed dictionary, such a key is removed from the result.
If the passed dictionary is optional and contains NULL, the result is also NULL.

Arguments:

  1. Dictionary.
  2. Aggregation factory.

Examples

SELECT DictAggregate(AsDict(
    AsTuple(1, AsList("foo", "bar")),
    AsTuple(2, AsList("baz", "qwe"))),
    AggregationFactory("Max"));
-- {1 : "foo", 2 : "qwe" }

SetIsDisjoint

Check that the dictionary doesn't intersect by keys with a list or another dictionary.

So there are two options to make a call:

  • With the Dict<K,V1> and List<K> arguments.
  • With the Dict<K,V1> and Dict<K,V2> arguments.

Examples

SELECT SetIsDisjoint(ToSet(AsList(1, 2, 3)), AsList(7, 4)); -- true
SELECT SetIsDisjoint(ToSet(AsList(1, 2, 3)), ToSet(AsList(3, 4))); -- false

SetIntersection

Construct intersection between two dictionaries based on keys.

Arguments:

  • Two dictionaries: Dict<K,V1> and Dict<K,V2>.
  • An optional function that combines the values from the source dictionaries to construct the values of the output dictionary. If such a function has the (K,V1,V2) -> U type, the result type is Dict<K,U>. If the function is not specified, the result type is Dict<K,Void>, and the values from the source dictionaries are ignored.

Examples

SELECT SetIntersection(ToSet(AsList(1, 2, 3)), ToSet(AsList(3, 4))); -- { 3 }
SELECT SetIntersection(
    AsDict(AsTuple(1, "foo"), AsTuple(3, "bar")),
    AsDict(AsTuple(1, "baz"), AsTuple(2, "qwe")),
    ($k, $a, $b) -> { RETURN AsTuple($a, $b) });
-- { 1 : ("foo", "baz") }

SetIncludes

Checking that the keys of the specified dictionary include all the elements of the list or the keys of the second dictionary.

So there are two options to make a call:

  • With the Dict<K,V1> and List<K> arguments.
  • With the Dict<K,V1> and Dict<K,V2> arguments.

Examples

SELECT SetIncludes(ToSet(AsList(1, 2, 3)), AsList(3, 4)); -- false
SELECT SetIncludes(ToSet(AsList(1, 2, 3)), ToSet(AsList(2, 3))); -- true

SetUnion

Constructs a union of two dictionaries based on keys.

Arguments:

  • Two dictionaries: Dict<K,V1> and Dict<K,V2>.
  • An optional function that combines the values from the source dictionaries to construct the values of the output dictionary. If such a function has the (K,V1?,V2?) -> U type, the result type is Dict<K,U>. If the function is not specified, the result type is Dict<K,Void>, and the values from the source dictionaries are ignored.

Examples

SELECT SetUnion(ToSet(AsList(1, 2, 3)), ToSet(AsList(3, 4))); -- { 1, 2, 3, 4 }
SELECT SetUnion(
    AsDict(AsTuple(1, "foo"), AsTuple(3, "bar")),
    AsDict(AsTuple(1, "baz"), AsTuple(2, "qwe")),
    ($k, $a, $b) -> { RETURN AsTuple($a, $b) });
-- { 1 : ("foo", "baz"), 2 : (null, "qwe"), 3 : ("bar", null) }

SetDifference

Construct a dictionary containing all the keys with their values in the first dictionary with no matching key in the second dictionary.

Examples

SELECT SetDifference(ToSet(AsList(1, 2, 3)), ToSet(AsList(3, 4))); -- { 1, 2 }
SELECT SetDifference(
    AsDict(AsTuple(1, "foo"), AsTuple(2, "bar")),
    ToSet(AsList(2, 3)));
-- { 1 : "foo" }

SetSymmetricDifference

Construct a symmetric difference between two dictionaries based on keys.

Arguments:

  • Two dictionaries: Dict<K,V1> and Dict<K,V2>.
  • An optional function that combines the values from the source dictionaries to construct the values of the output dictionary. If such a function has the (K,V1?,V2?) -> U type, the result type is Dict<K,U>. If the function is not specified, the result type is Dict<K,Void>, and the values from the source dictionaries are ignored.

Examples

SELECT SetSymmetricDifference(ToSet(AsList(1, 2, 3)), ToSet(AsList(3, 4))); -- { 1, 2, 4 }
SELECT SetSymmetricDifference(
    AsDict(AsTuple(1, "foo"), AsTuple(3, "bar")),
    AsDict(AsTuple(1, "baz"), AsTuple(2, "qwe")),
    ($k, $a, $b) -> { RETURN AsTuple($a, $b) });
-- { 2 : (null, "qwe"), 3 : ("bar", null) }
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