union() Function

Function

union( array1, array2 )

Returns all unique elements from the given arrays.

Parameters

Keyword Type Description

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 duplicates from an array

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

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}}

Null values and empty lists

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

Scalar values are cast to arrays with a single entry:

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

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