docs-v2/content/v2.0/reference/flux/stdlib/experimental/aligntime.md

title	description	menu	weight
experimental.alignTime() function	The `experimental.alignTime()` function aligns input tables to a common start time.	v2_0_ref name parent experimental.alignTime Experimental	302

The experimental.alignTime() function aligns input tables to a common start time.

Function type: Transformation

import "experimental"

experimental.alignTime(
  alignTo: 1970-01-01T00:00:00.000000000Z
)

Parameters

alignTo

The UTC time to align tables to. Default is 1970-01-01T00:00:00Z.

Data type: Time

Examples

Compare values month-over-month

import "experimental"

from(bucket: "example-bucket")
  |> range(start: -12mo)
  |> filter(fn: (r) => r._measurement == "example-measurement")
  |> window(every: 1mo)
  |> experimental.alignTime()

Given the following input:

_time	_value
2020-01-01T00:00:00Z	32.1
2020-01-02T00:00:00Z	32.9
2020-01-03T00:00:00Z	33.2
2020-01-04T00:00:00Z	34.0
2020-02-01T00:00:00Z	38.3
2020-02-02T00:00:00Z	38.4
2020-02-03T00:00:00Z	37.8
2020-02-04T00:00:00Z	37.5

The following functions:

1. Window data by calendar month creating two separate tables (one for January and one for February).
2. Align tables to 2020-01-01T00:00:00Z.

//...
  |> window(every: 1mo)
  |> alignTime(alignTo: 2020-01-01T00:00:00Z)

And output:

{{< flex >}} {{% flex-content %}}

_time	_value
2020-01-01T00:00:00Z	32.1
2020-01-02T00:00:00Z	32.9
2020-01-03T00:00:00Z	33.2
2020-01-04T00:00:00Z	34.0
{{% /flex-content %}}
{{% flex-content %}}
_time	_value
:-----	------:
2020-01-01T00:00:00Z	38.3
2020-01-02T00:00:00Z	38.4
2020-01-03T00:00:00Z	37.8
2020-01-04T00:00:00Z	37.5
{{% /flex-content %}}
{{< /flex >}}

Each output table represents data from a calendar month. When visualized, data is still grouped by month, but timestamps are aligned to a common start time and values can be compared by time.