docs-v2/content/flux/v0.x/stdlib/experimental/unique.md

title	description	menu	weight	flux/v0.x/tags	introduced
experimental.unique() function	`experimental.unique()` returns all records containing unique values in the `_value` column.	flux_0_x_ref name parent identifier experimental.unique experimental experimental/unique	101	transformations selectors	0.112.0

experimental.unique() returns all records containing unique values in the _value column.

null is considered a unique value.

Function behavior

• Outputs a single table for each input table.
• Outputs a single record for each unique value in an input table.
• Leaves group keys, columns, and values unmodified.
• Drops emtpy tables.

Function type signature

(<-tables: stream[{A with _value: B}]) => stream[{A with _value: B}]

{{% caption %}}For more information, see Function type signatures.{{% /caption %}}

Parameters

tables

Input data. Default is piped-forward data (<-).

Examples

Return rows with unique values in each input table

import "experimental"
import "sampledata"

sampledata.int(includeNull: true)
    |> experimental.unique()

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Input data

_time	_value	*tag
2021-01-01T00:00:00Z	-2	t1
2021-01-01T00:00:10Z		t1
2021-01-01T00:00:20Z	7	t1
2021-01-01T00:00:30Z		t1
2021-01-01T00:00:40Z		t1
2021-01-01T00:00:50Z	4	t1

_time	_value	*tag
2021-01-01T00:00:00Z		t2
2021-01-01T00:00:10Z	4	t2
2021-01-01T00:00:20Z	-3	t2
2021-01-01T00:00:30Z	19	t2
2021-01-01T00:00:40Z		t2
2021-01-01T00:00:50Z	1	t2

Output data

_time	_value	*tag
2021-01-01T00:00:00Z	-2	t1
2021-01-01T00:00:10Z		t1
2021-01-01T00:00:20Z	7	t1
2021-01-01T00:00:50Z	4	t1

_time	_value	*tag
2021-01-01T00:00:00Z		t2
2021-01-01T00:00:10Z	4	t2
2021-01-01T00:00:20Z	-3	t2
2021-01-01T00:00:30Z	19	t2
2021-01-01T00:00:50Z	1	t2

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