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

You can experiment with this function in the test box below.

Test Input

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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