docs-v2/content/flux/v0/stdlib/universe/mean.md

title	description	menu	weight	flux/v0/tags	introduced
mean() function	`mean()` returns the average of non-null values in a specified column from each input table.	flux_v0_ref name parent identifier mean universe universe/mean	101	transformations aggregates	0.7.0

mean() returns the average of non-null values in a specified column from each input table.

Function type signature

(<-tables: stream[A], ?column: string) => stream[B] where A: Record, B: Record

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Parameters

column

Column to use to compute means. Default is _value.

tables

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

Examples

Return the average of values in each input table

import "sampledata"

sampledata.int()
    |> mean()

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Input data

_time	_value	*tag
2021-01-01T00:00:00Z	-2	t1
2021-01-01T00:00:10Z	10	t1
2021-01-01T00:00:20Z	7	t1
2021-01-01T00:00:30Z	17	t1
2021-01-01T00:00:40Z	15	t1
2021-01-01T00:00:50Z	4	t1

_time	_value	*tag
2021-01-01T00:00:00Z	19	t2
2021-01-01T00:00:10Z	4	t2
2021-01-01T00:00:20Z	-3	t2
2021-01-01T00:00:30Z	19	t2
2021-01-01T00:00:40Z	13	t2
2021-01-01T00:00:50Z	1	t2

Output data

*tag	_value
t1	8.5

*tag	_value
t2	8.833333333333334

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