FILTER_ARRAY

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Syntax

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Scalar

filter_array(array,lambda)

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Filter form (scalar)

filter(array,lambda)

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Arguments

• T is the array element type: BOOLEAN, TINYINT, SMALLINT, INTEGER, BIGINT, FLOAT, DOUBLE, DECIMAL(p, s), STRING, BINARY, DATE, TIME, TIMESTAMP, ARRAY, MAP or STRUCT.

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Scalar, filter form

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Returns

• Type: ARRAY<T>
• Possible values: Retained input elements.
• NULL behavior: NULL array returns NULL; NULL elements are passed to the lambda. FALSE and NULL predicates discard the element.
• Shape: Zero through input number of elements.
• Ordering: Input encounter order.

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Properties

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Usage notes

• The optional lambda index is zero-based.
• The optional lambda index is BIGINT and starts at 0 for each input array.
• INTEGER and INT mean the same type; STRING means VARCHAR text. NULL can be used with a supported type. Cast NULL explicitly when its type would otherwise be unclear.

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Examples

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Typical behavior

SELECT filter(ARRAY[1, 2, 3], x -> x > 1) AS "value";

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Filter strings

SELECT filter_array(ARRAY('ant', 'bear', 'cat'), x -> length(x) > 3) AS long_words;

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Limitations

• The same input gives repeatable results only when the supplied lambda does. Avoid random or other changing expressions when you need reproducible results.