docs-v2/content/flux/v0.x/stdlib/universe/contains.md

title	description	menu	weight	introduced
contains() function	`contains()` tests if an array contains a specified value and returns `true` or `false`.	flux_0_x_ref name parent identifier contains universe universe/contains	101	0.19.0

contains() tests if an array contains a specified value and returns true or false.

Function type signature

(set: [A], value: A) => bool where A: Nullable

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

Parameters

value

({{< req >}}) Value to search for.

set

({{< req >}}) Array to search.

Examples

Filter on a set of specific fields

fields = ["f1", "f2"]

data
    |> filter(fn: (r) => contains(value: r._field, set: fields))

{{< expand-wrapper >}} {{% expand "View example input and output" %}}

Input data

_time	_value	*tag	_measurement	*_field
2021-01-01T00:00:00Z	-2	t1	m	f1
2021-01-01T00:00:50Z	4	t1	m	f1

_time	_value	*tag	_measurement	*_field
2021-01-01T00:00:10Z	4	t2	m	f1
2021-01-01T00:00:20Z	-3	t2	m	f1
2021-01-01T00:00:50Z	1	t2	m	f1

_time	_value	*tag	_measurement	*_field
2021-01-01T00:00:10Z	10	t1	m	f2
2021-01-01T00:00:20Z	7	t1	m	f2

_time	_value	*tag	_measurement	*_field
2021-01-01T00:00:30Z	17	t1	m	f3
2021-01-01T00:00:40Z	15	t1	m	f3

_time	_value	*tag	_measurement	*_field
2021-01-01T00:00:00Z	19	t2	m	f3
2021-01-01T00:00:30Z	19	t2	m	f3
2021-01-01T00:00:40Z	13	t2	m	f3

Output data

_time	_value	*tag	_measurement	*_field
2021-01-01T00:00:00Z	-2	t1	m	f1
2021-01-01T00:00:50Z	4	t1	m	f1

_time	_value	*tag	_measurement	*_field
2021-01-01T00:00:10Z	4	t2	m	f1
2021-01-01T00:00:20Z	-3	t2	m	f1
2021-01-01T00:00:50Z	1	t2	m	f1

_time	_value	*tag	_measurement	*_field
2021-01-01T00:00:10Z	10	t1	m	f2
2021-01-01T00:00:20Z	7	t1	m	f2

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