docs-v2/content/flux/v0/stdlib/universe/stateduration.md

title	description	menu	weight	flux/v0/tags	introduced
stateDuration() function	`stateDuration()` returns the cumulative duration of a given state.	flux_v0_ref name parent identifier stateDuration universe universe/stateDuration	101	transformations	0.7.0

stateDuration() returns the cumulative duration of a given state.

The state is defined by the fn predicate function. For each consecutive record that evaluates to true, the state duration is incremented by the duration of time between records using the specified unit. When a record evaluates to false, the value is set to -1 and the state duration is reset. If the record generates an error during evaluation, the point is discarded, and does not affect the state duration.

The state duration is added as an additional column to each record. The duration is represented as an integer in the units specified.

Note: As the first point in the given state has no previous point, its state duration will be 0.

Function type signature

(
    <-tables: stream[A],
    fn: (r: A) => bool,
    ?column: string,
    ?timeColumn: string,
    ?unit: duration,
) => stream[B] where A: Record, B: Record

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

Parameters

fn

({{< req >}}) Predicate function that identifies the state of a record.

column

Column to store the state duration in. Default is stateDuration.

timeColumn

Time column to use to calculate elapsed time between rows. Default is _time.

unit

Unit of time to use to increment state duration. Default is 1s (seconds).

Example units:

• 1ns (nanoseconds)
• 1us (microseconds)
• 1ms (milliseconds)
• 1s (seconds)
• 1m (minutes)
• 1h (hours)
• 1d (days)

tables

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

Examples

Return the time spent in a specified state

import "sampledata"

sampledata.int()
    |> stateDuration(fn: (r) => r._value < 15)

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Input data

_time	_value	*tag
2021-01-01T00:00:00Z	-2	t1
2021-01-01T00:00:10Z	10	t1
2021-01-01T00:00:20Z	7	t1
2021-01-01T00:00:30Z	17	t1
2021-01-01T00:00:40Z	15	t1
2021-01-01T00:00:50Z	4	t1

_time	_value	*tag
2021-01-01T00:00:00Z	19	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	13	t2
2021-01-01T00:00:50Z	1	t2

Output data

_time	_value	*tag	stateDuration
2021-01-01T00:00:00Z	-2	t1	0
2021-01-01T00:00:10Z	10	t1	10
2021-01-01T00:00:20Z	7	t1	20
2021-01-01T00:00:30Z	17	t1	-1
2021-01-01T00:00:40Z	15	t1	-1
2021-01-01T00:00:50Z	4	t1	0

_time	_value	*tag	stateDuration
2021-01-01T00:00:00Z	19	t2	-1
2021-01-01T00:00:10Z	4	t2	0
2021-01-01T00:00:20Z	-3	t2	10
2021-01-01T00:00:30Z	19	t2	-1
2021-01-01T00:00:40Z	13	t2	0
2021-01-01T00:00:50Z	1	t2	10

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