119 lines
2.9 KiB
Markdown
119 lines
2.9 KiB
Markdown
---
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title: highestMax() function
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description: >
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`highestMax()` selects the record with the highest value in the specified `column`
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from each input table and returns the highest `n` records.
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menu:
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flux_v0_ref:
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name: highestMax
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parent: universe
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identifier: universe/highestMax
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weight: 101
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flux/v0/tags: [transformations, selectors]
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introduced: 0.7.0
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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#L4199-L4209
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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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`highestMax()` selects the record with the highest value in the specified `column`
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from each input table and returns the highest `n` records.
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**Note:** `highestMax()` drops empty tables.
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##### Function type signature
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```js
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(<-tables: stream[A], n: int, ?column: string, ?groupColumns: [string]) => stream[A] where A: 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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### n
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({{< req >}})
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Number of records to return.
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### column
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Column to evaluate. Default is `_value`.
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### groupColumns
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List of columns to group by. Default is `[]`.
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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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### Return the highest two values from a stream of tables
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```js
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import "sampledata"
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sampledata.int()
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|> highestMax(n: 2, groupColumns: ["tag"])
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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 |
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| -------------------- | ------- | ---- |
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| 2021-01-01T00:00:00Z | 19 | t2 |
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| 2021-01-01T00:00:30Z | 17 | t1 |
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{{% /expand %}}
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{{< /expand-wrapper >}}
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