187 lines
5.1 KiB
Markdown
187 lines
5.1 KiB
Markdown
---
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title: experimental.fill() function
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description: >
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`experimental.fill()` replaces all null values in the `_value` column with a non-null value.
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menu:
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flux_v0_ref:
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name: experimental.fill
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parent: experimental
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identifier: experimental/fill
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weight: 101
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flux/v0/tags: [transformations]
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introduced: 0.112.0
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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/experimental/experimental.flux#L1091-L1095
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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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`experimental.fill()` replaces all null values in the `_value` column with a non-null value.
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##### Function type signature
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```js
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(<-tables: stream[{B with _value: A}], ?usePrevious: bool, ?value: A) => stream[{B with _value: A}]
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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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### value
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Value to replace null values with.
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Data type must match the type of the `_value` column.
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### usePrevious
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Replace null values with the value of the previous non-null row.
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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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- [Fill null values with a specified non-null value](#fill-null-values-with-a-specified-non-null-value)
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- [Fill null values with the previous non-null value](#fill-null-values-with-the-previous-non-null-value)
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### Fill null values with a specified non-null value
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```js
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import "experimental"
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import "sampledata"
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sampledata.int(includeNull: true)
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|> experimental.fill(value: 0)
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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 | | t1 |
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| 2021-01-01T00:00:20Z | 7 | t1 |
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| 2021-01-01T00:00:30Z | | t1 |
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| 2021-01-01T00:00:40Z | | 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 | | 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 | | 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 |
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| -------------------- | ------- | ---- |
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| 2021-01-01T00:00:00Z | -2 | t1 |
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| 2021-01-01T00:00:10Z | 0 | t1 |
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| 2021-01-01T00:00:20Z | 7 | t1 |
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| 2021-01-01T00:00:30Z | 0 | t1 |
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| 2021-01-01T00:00:40Z | 0 | 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 | 0 | 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 | 0 | t2 |
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| 2021-01-01T00:00:50Z | 1 | t2 |
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{{% /expand %}}
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{{< /expand-wrapper >}}
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### Fill null values with the previous non-null value
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```js
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import "experimental"
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import "sampledata"
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sampledata.int(includeNull: true)
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|> experimental.fill(usePrevious: true)
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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 | | t1 |
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| 2021-01-01T00:00:20Z | 7 | t1 |
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| 2021-01-01T00:00:30Z | | t1 |
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| 2021-01-01T00:00:40Z | | 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 | | 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 | | 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 |
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| -------------------- | ------- | ---- |
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| 2021-01-01T00:00:00Z | -2 | t1 |
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| 2021-01-01T00:00:10Z | -2 | t1 |
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| 2021-01-01T00:00:20Z | 7 | t1 |
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| 2021-01-01T00:00:30Z | 7 | t1 |
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| 2021-01-01T00:00:40Z | 7 | 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 | | 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 | 19 | t2 |
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| 2021-01-01T00:00:50Z | 1 | t2 |
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{{% /expand %}}
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{{< /expand-wrapper >}}
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