Back to Influxdb

truncateTimeColumn() function

content/flux/v0/stdlib/universe/truncatetimecolumn.md

latest3.3 KB
Original Source
<!------------------------------------------------------------------------------ IMPORTANT: This page was generated from comments in the Flux source code. Any edits made directly to this page will be overwritten the next time the documentation is generated. To make updates to this documentation, update the function comments above the function definition in the Flux source code: https://github.com/influxdata/flux/blob/master/stdlib/universe/universe.flux#L4595-L4597 Contributing to Flux: https://github.com/influxdata/flux#contributing Fluxdoc syntax: https://github.com/influxdata/flux/blob/master/docs/fluxdoc.md ------------------------------------------------------------------------------->

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
js
(<-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

js
import "sampledata"

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

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

Input data

_time_value*tag
2021-01-01T00:00:00Z-2t1
2021-01-01T00:00:10Z10t1
2021-01-01T00:00:20Z7t1
2021-01-01T00:00:30Z17t1
2021-01-01T00:00:40Z15t1
2021-01-01T00:00:50Z4t1
_time_value*tag
2021-01-01T00:00:00Z19t2
2021-01-01T00:00:10Z4t2
2021-01-01T00:00:20Z-3t2
2021-01-01T00:00:30Z19t2
2021-01-01T00:00:40Z13t2
2021-01-01T00:00:50Z1t2

Output data

_time_value*tag
2021-01-01T00:00:00Z-2t1
2021-01-01T00:00:00Z10t1
2021-01-01T00:00:00Z7t1
2021-01-01T00:00:00Z17t1
2021-01-01T00:00:00Z15t1
2021-01-01T00:00:00Z4t1
_time_value*tag
2021-01-01T00:00:00Z19t2
2021-01-01T00:00:00Z4t2
2021-01-01T00:00:00Z-3t2
2021-01-01T00:00:00Z19t2
2021-01-01T00:00:00Z13t2
2021-01-01T00:00:00Z1t2

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