130 lines
3.4 KiB
Markdown
130 lines
3.4 KiB
Markdown
---
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title: elapsed() function
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description: >
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`elapsed()` returns the time between subsequent records.
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menu:
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flux_v0_ref:
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name: elapsed
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parent: universe
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identifier: universe/elapsed
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weight: 101
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flux/v0/tags: [transformations]
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introduced: 0.36.0
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---
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<!------------------------------------------------------------------------------
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IMPORTANT: This page was generated from comments in the Flux source code. Any
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edits made directly to this page will be overwritten the next time the
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documentation is generated.
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To make updates to this documentation, update the function comments above the
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function definition in the Flux source code:
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https://github.com/influxdata/flux/blob/master/stdlib/universe/universe.flux#L525-L533
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Contributing to Flux: https://github.com/influxdata/flux#contributing
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Fluxdoc syntax: https://github.com/influxdata/flux/blob/master/docs/fluxdoc.md
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------------------------------------------------------------------------------->
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`elapsed()` returns the time between subsequent records.
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For each input table, `elapsed()` returns the same table without the first row
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(because there is no previous time to derive the elapsed time from) and an
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additional column containing the elapsed time.
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##### Function type signature
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```js
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(<-tables: stream[A], ?columnName: string, ?timeColumn: string, ?unit: duration) => stream[B] where A: Record, B: Record
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```
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{{% caption %}}
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For more information, see [Function type signatures](/flux/v0/function-type-signatures/).
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{{% /caption %}}
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## Parameters
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### unit
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Unit of time used in the calculation. Default is `1s`.
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### timeColumn
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Column to use to compute the elapsed time. Default is `_time`.
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### columnName
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Column to store elapsed times in. Default is `elapsed`.
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### tables
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Input data. Default is piped-forward data (`<-`).
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## Examples
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### Calculate the time between points in seconds
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```js
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import "sampledata"
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sampledata.int()
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|> elapsed(unit: 1s)
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```
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{{< expand-wrapper >}}
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{{% expand "View example input and output" %}}
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#### Input data
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| _time | _value | *tag |
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| -------------------- | ------- | ---- |
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| 2021-01-01T00:00:00Z | -2 | t1 |
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| 2021-01-01T00:00:10Z | 10 | t1 |
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| 2021-01-01T00:00:20Z | 7 | t1 |
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| 2021-01-01T00:00:30Z | 17 | t1 |
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| 2021-01-01T00:00:40Z | 15 | t1 |
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| 2021-01-01T00:00:50Z | 4 | t1 |
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| _time | _value | *tag |
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| -------------------- | ------- | ---- |
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| 2021-01-01T00:00:00Z | 19 | t2 |
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| 2021-01-01T00:00:10Z | 4 | t2 |
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| 2021-01-01T00:00:20Z | -3 | t2 |
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| 2021-01-01T00:00:30Z | 19 | t2 |
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| 2021-01-01T00:00:40Z | 13 | t2 |
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| 2021-01-01T00:00:50Z | 1 | t2 |
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#### Output data
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| _time | _value | *tag | elapsed |
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| -------------------- | ------- | ---- | -------- |
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| 2021-01-01T00:00:10Z | 10 | t1 | 10 |
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| 2021-01-01T00:00:20Z | 7 | t1 | 10 |
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| 2021-01-01T00:00:30Z | 17 | t1 | 10 |
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| 2021-01-01T00:00:40Z | 15 | t1 | 10 |
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| 2021-01-01T00:00:50Z | 4 | t1 | 10 |
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| _time | _value | *tag | elapsed |
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| -------------------- | ------- | ---- | -------- |
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| 2021-01-01T00:00:10Z | 4 | t2 | 10 |
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| 2021-01-01T00:00:20Z | -3 | t2 | 10 |
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| 2021-01-01T00:00:30Z | 19 | t2 | 10 |
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| 2021-01-01T00:00:40Z | 13 | t2 | 10 |
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| 2021-01-01T00:00:50Z | 1 | t2 | 10 |
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{{% /expand %}}
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{{< /expand-wrapper >}}
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