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

title	description	menu	weight	flux/v0/tags	introduced
truncateTimeColumn() function	`truncateTimeColumn()` truncates all input time values in the `_time` to a specified unit.	flux_v0_ref name parent identifier truncateTimeColumn universe universe/truncateTimeColumn	101	transformations date/time	0.37.0

truncateTimeColumn() truncates all input time values in the _time to a specified unit.

Truncate to weeks

When truncating a time value to the week (1w), weeks are determined using the Unix epoch (1970-01-01T00:00:00Z UTC). The Unix epoch was on a Thursday, so all calculated weeks begin on Thursday.

Function type signature

(<-tables: stream[{B with _time: C}], unit: duration, ?timeColumn: A) => stream[{B with _time: C, _time: time}] where C: Timeable

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

Parameters

unit

({{< req >}}) Unit of time to truncate to.

Example units:

• 1ns (nanosecond)
• 1us (microsecond)
• 1ms (millisecond)
• 1s (second)
• 1m (minute)
• 1h (hour)
• 1d (day)
• 1w (week)
• 1mo (month)
• 1y (year)

timeColumn

Time column to truncate. Default is _time.

Note: Currently, assigning a custom value to this parameter will have no effect.

tables

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

Examples

Truncate all time values to the minute

import "sampledata"

sampledata.int()
    |> truncateTimeColumn(unit: 1m)

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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

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

_time	_value	*tag
2021-01-01T00:00:00Z	19	t2
2021-01-01T00:00:00Z	4	t2
2021-01-01T00:00:00Z	-3	t2
2021-01-01T00:00:00Z	19	t2
2021-01-01T00:00:00Z	13	t2
2021-01-01T00:00:00Z	1	t2

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