100 lines
2.4 KiB
Markdown
100 lines
2.4 KiB
Markdown
---
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title: hourSelection() function
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description: >
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The `hourSelection()` function retains all rows with time values in a specified hour range.
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Hours are specified in military time.
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aliases:
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- /influxdb/v2.0/reference/flux/functions/transformations/hourselection
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- /influxdb/v2.0/reference/flux/functions/built-in/transformations/hourselection/
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- /influxdb/v2.0/reference/flux/stdlib/built-in/transformations/hourselection/
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- /influxdb/cloud/reference/flux/stdlib/built-in/transformations/hourselection/
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menu:
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flux_0_x_ref:
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name: hourSelection
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parent: universe
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weight: 102
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flux/v0.x/tags: [transformations, date/time]
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introduced: 0.39.0
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---
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The `hourSelection()` function retains all rows with time values in a specified hour range.
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```js
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hourSelection(
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start: 9,
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stop: 17,
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timeColumn: "_time",
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)
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```
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## Parameters
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### start {data-type="int"}
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({{< req >}})
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The first hour of the hour range (inclusive).
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Hours range from `[0-23]`.
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### stop {data-type="int"}
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({{< req >}})
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The last hour of the hour range (inclusive).
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Hours range from `[0-23]`.
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### timeColumn {data-type="string"}
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The column that contains the time value.
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Default is `"_time"`.
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### tables {data-type="stream of tables"}
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Input data.
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Default is piped-forward data ([`<-`](/flux/v0.x/spec/expressions/#pipe-expressions)).
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## Examples
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The following example uses [`generate.from()`](/flux/v0.x/stdlib/generate/from/)
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to generate sample data and show how `covariance()` transforms data.
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#### Filter by business hours
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```js
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import "generate"
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data = generate.from(
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count: 8,
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fn: (n) => n * n,
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start: 2021-01-01T00:00:00Z,
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stop: 2021-01-02T00:00:00Z,
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)
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data
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|> hourSelection(start: 9, stop: 17)
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```
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{{< expand-wrapper >}}
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{{% expand "View input and output" %}}
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{{< flex >}}
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{{% flex-content %}}
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##### Input data
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| _time | _value |
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| :------------------- | -----: |
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| 2021-01-01T00:00:00Z | 0 |
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| 2021-01-01T03:00:00Z | 1 |
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| 2021-01-01T06:00:00Z | 4 |
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| 2021-01-01T09:00:00Z | 9 |
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| 2021-01-01T12:00:00Z | 16 |
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| 2021-01-01T15:00:00Z | 25 |
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| 2021-01-01T18:00:00Z | 36 |
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| 2021-01-01T21:00:00Z | 49 |
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{{% /flex-content %}}
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{{% flex-content %}}
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##### Output data
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| _time | _value |
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| :------------------- | -----: |
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| 2021-01-01T09:00:00Z | 9 |
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| 2021-01-01T12:00:00Z | 16 |
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| 2021-01-01T15:00:00Z | 25 |
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{{% /flex-content %}}
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{{< /flex >}}
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{{% /expand %}}
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{{< /expand-wrapper >}}
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