61 lines
1.6 KiB
Markdown
61 lines
1.6 KiB
Markdown
---
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title: experimental.stddev() function
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description: >
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The `experimental.stddev()` function computes the standard deviation of non-null
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values in the `_value` column for each input table.
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menu:
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flux_0_x_ref:
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name: experimental.stddev
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parent: experimental
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weight: 302
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aliases:
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- /influxdb/v2.0/reference/flux/stdlib/experimental/stddev/
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- /influxdb/cloud/reference/flux/stdlib/experimental/stddev/
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related:
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- /flux/v0.x/stdlib/universe/stddev/
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- /{{< latest "influxdb" "v1" >}}/query_language/functions/#stddev, InfluxQL – STDDEV()
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flux/v0.x/tags: [transformations, aggregates]
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introduced: 0.107.0
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---
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The `experimental.stddev()` function computes the standard deviation of non-null
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values in the `_value` column for each input table.
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_`experimental.stddev()` is an [aggregate function](/flux/v0.x/function-types/#aggregates)._
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```js
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import "experimental"
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experimental.stddev(mode: "sample")
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```
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## Parameters
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### mode {data-type="string"}
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The standard deviation mode or type of standard deviation to calculate.
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Defaults to `"sample"`.
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**Available options:**
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- [sample](#sample)
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- [population](#population)
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##### sample
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Calculate the sample standard deviation where the data is considered to be part of a larger population.
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##### population
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Calculate the population standard deviation where the data is considered a population of its own.
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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 (`<-`).
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## Examples
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```js
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import "experimental"
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from(bucket: "example-bucket")
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|> range(start: -5m)
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|> filter(fn: (r) => r._measurement == "cpu" and r._field == "usage_system")
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|> experimental.stddev()
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```
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