98 lines
3.2 KiB
Markdown
98 lines
3.2 KiB
Markdown
---
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title: stateCount() function
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description: The `stateCount()` function computes the number of consecutive records in a given state.
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aliases:
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- /influxdb/v2.0/reference/flux/functions/transformations/statecount
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- /influxdb/v2.0/reference/flux/functions/built-in/transformations/statecount/
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- /influxdb/v2.0/reference/flux/stdlib/built-in/transformations/statecount/
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- /influxdb/cloud/reference/flux/stdlib/built-in/transformations/statecount/
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menu:
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flux_0_x_ref:
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name: stateCount
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parent: universe
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weight: 102
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flux/v0.x/tags: [transformations]
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related:
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- /{{< latest "influxdb" >}}/query-data/flux/monitor-states/
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introduced: 0.7.0
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---
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The `stateCount()` function computes the number of consecutive records in a given state.
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The state is defined via the function `fn`.
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For each consecutive point that evaluates as `true`, the state count is incremented.
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When a point evaluates as `false`, the state count is reset.
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The state count is added as an additional column to each record.
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```js
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stateCount(fn: (r) => r._field == "state", column: "stateCount")
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```
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_If the expression generates an error during evaluation, the point is discarded
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and does not affect the state count._
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## Parameters
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{{% note %}}
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Make sure `fn` parameter names match each specified parameter.
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To learn why, see [Match parameter names](/flux/v0.x/spec/data-model/#match-parameter-names).
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{{% /note %}}
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### fn {data-type="function"}
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({{< req >}})
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A single argument function that evaluates true or false to identify the state of the record.
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Records are passed to the function.
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Those that evaluate to `true` increment the state count.
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Those that evaluate to `false` reset the state count.
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### column {data-type="string"}
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Name of the column added to each record that contains the incremented state count.
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Default is `stateCount`.
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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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{{% flux/sample-example-intro %}}
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```js
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import "sampledata"
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sampledata.int()
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|> stateCount(fn: (r) => r._value > 10)
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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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{{% flux/sample "int" %}}
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{{% /flex-content %}}
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{{% flex-content %}}
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##### Output data
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| _time | tag | _value | stateCount |
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| :------------------- | :-- | -----: | ---------: |
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| 2021-01-01T00:00:00Z | t1 | -2 | -1 |
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| 2021-01-01T00:00:10Z | t1 | 10 | -1 |
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| 2021-01-01T00:00:20Z | t1 | 7 | -1 |
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| 2021-01-01T00:00:30Z | t1 | 17 | 1 |
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| 2021-01-01T00:00:40Z | t1 | 15 | 2 |
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| 2021-01-01T00:00:50Z | t1 | 4 | -1 |
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| _time | tag | _value | stateCount |
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| :------------------- | :-- | -----: | ---------: |
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| 2021-01-01T00:00:00Z | t2 | 19 | 1 |
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| 2021-01-01T00:00:10Z | t2 | 4 | -1 |
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| 2021-01-01T00:00:20Z | t2 | -3 | -1 |
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| 2021-01-01T00:00:30Z | t2 | 19 | 1 |
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| 2021-01-01T00:00:40Z | t2 | 13 | 2 |
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| 2021-01-01T00:00:50Z | t2 | 1 | -1 |
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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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