docs-v2/content/flux/v0/stdlib/internal/promql/changes.md

title	description	menu	weight
promql.changes() function	`promql.changes()` implements functionality equivalent to [PromQL's `changes()` function](https://prometheus.io/docs/prometheus/latest/querying/functions/#changes).	flux_v0_ref name parent identifier promql.changes internal/promql internal/promql/changes	201

promql.changes() implements functionality equivalent to PromQL's changes() function.

Important: The internal/promql package is not meant for external use.

Function type signature

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

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

Parameters

tables

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

Examples

Return the number of times that values in a series change

import "internal/promql"
import "sampledata"

sampledata.float()
    |> promql.changes()

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Input data

_time	*tag	_value
2021-01-01T00:00:00Z	t1	-2.18
2021-01-01T00:00:10Z	t1	10.92
2021-01-01T00:00:20Z	t1	7.35
2021-01-01T00:00:30Z	t1	17.53
2021-01-01T00:00:40Z	t1	15.23
2021-01-01T00:00:50Z	t1	4.43

_time	*tag	_value
2021-01-01T00:00:00Z	t2	19.85
2021-01-01T00:00:10Z	t2	4.97
2021-01-01T00:00:20Z	t2	-3.75
2021-01-01T00:00:30Z	t2	19.77
2021-01-01T00:00:40Z	t2	13.86
2021-01-01T00:00:50Z	t2	1.86

Output data

*tag	_value
t1	5

*tag	_value
t2	5

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