union() Function

Returns all unique elements from the given arrays.

Syntax

union( array1, array2, … )

array1: (Any Type Array) Array to combine.

array2: (Any Type Array) Array to combine.

Returns

Any Type Array, matching the type of the inputs

Examples

Find the superset of values from two integer arrays:

union({1, 2, 3, 4}, {3, 4, 5, 6}) returns and array with 1, 2, 3, 4, 5, 6

Remove the duplicates from an array by comparing it with an empty array of the same type:

union({1, 2, 3, 4, 1, 2}, tointeger({})) returns and array with 1, 2, 3, 4

Values are matched with case sensitivity:

union({"a", "b"}, {"a", "B"}) returns and array with a, b, B

Array types must match:

union({"a", "b"}, {1, 2}) returns the following error: Invalid types, can only act on data of the same type.

NOTE: Use either the conversion functions or the cast() function to convert to the appropriate type.

union({"a", "b"}, tostring({1, 2})) returns and array with a, b, 1, 2

Null values are included as long as they are of the correct types (nulls of an incorrect type throw a type mismatch error):

union({"a", "b"}, {"c", ""}) returns and array with a, b, c, <null>

Empty lists are ignored as long as they are of the correct types (empty lists of an incorrect type throw a type mismatch error):

union(tointeger({}), {1, 2}) returns and array with 1, 2

Scalar values are cast to arrays with a single entry:

union(1, {2, 3}) returns and array with 1, 2, 3

Every field of a CDT or dictionary must match to be treated as identical:

union({a: 1, b: 2}, {a: 1, b: 2, c: 3}) returns {{a: 1, b: 2}, {a: 1, b: 2, c: 3}} union({a: 1, b: 2}, {a: 1, b: 2}) returns {{a: 1, b: 2}}

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