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experimental.stddev() function

content/flux/v0/stdlib/experimental/stddev.md

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experimental.stddev() returns the standard deviation of non-null values in the _value column for each input table.

Standard deviation modes

The following modes are available when calculating the standard deviation of data.

sample

Calculate the sample standard deviation where the data is considered to be part of a larger population.

population

Calculate the population standard deviation where the data is considered a population of its own.

Function type signature
js
(<-tables: stream[{A with _value: float}], ?mode: string) => stream[{A with _value: float}]

{{% caption %}} For more information, see Function type signatures. {{% /caption %}}

Parameters

mode

Standard deviation mode or type of standard deviation to calculate. Default is sample.

Available options:

  • sample
  • population

tables

Input data. Default is piped-forward data (<-).

Examples

Return the standard deviation in input tables

js
import "experimental"
import "sampledata"

sampledata.float()
    |> experimental.stddev()

{{< expand-wrapper >}} {{% expand "View example input and output" %}}

Input data

_time*tag_value
2021-01-01T00:00:00Zt1-2.18
2021-01-01T00:00:10Zt110.92
2021-01-01T00:00:20Zt17.35
2021-01-01T00:00:30Zt117.53
2021-01-01T00:00:40Zt115.23
2021-01-01T00:00:50Zt14.43
_time*tag_value
2021-01-01T00:00:00Zt219.85
2021-01-01T00:00:10Zt24.97
2021-01-01T00:00:20Zt2-3.75
2021-01-01T00:00:30Zt219.77
2021-01-01T00:00:40Zt213.86
2021-01-01T00:00:50Zt21.86

Output data

*tag_value
t17.263244454099008
*tag_value
t29.85926704510364

{{% /expand %}} {{< /expand-wrapper >}}