Influxdata
/
docs-v2
mirror of https://github.com/influxdata/docs-v2.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
docs-v2/content/flux/v0/stdlib/universe/group.md

302 lines
8.3 KiB
Markdown
Raw Permalink Blame History

---
title: group() function
description: >
`group()` regroups input data by modifying group key of input tables.
menu:
flux_v0_ref:
name: group
parent: universe
identifier: universe/group
weight: 101
flux/v0/tags: [transformations]
introduced: 0.7.0
---
<!------------------------------------------------------------------------------
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#L752-L754
Contributing to Flux: https://github.com/influxdata/flux#contributing
Fluxdoc syntax: https://github.com/influxdata/flux/blob/master/docs/fluxdoc.md
------------------------------------------------------------------------------->
`group()` regroups input data by modifying group key of input tables.
**Note**: Group does not guarantee sort order.
To ensure data is sorted correctly, use `sort()` after `group()`.
##### Function type signature
```js
(<-tables: stream[A], ?columns: [string], ?mode: string) => stream[A] where A: Record
```
{{% caption %}}
For more information, see [Function type signatures](/flux/v0/function-type-signatures/).
{{% /caption %}}
## Parameters
### columns
List of columns to use in the grouping operation. Default is `[]`.
**Note**: When `columns` is set to an empty array, `group()` ungroups
all data merges it into a single output table.
### mode
Grouping mode. Default is `by`.
**Available modes**:
- **by**: Group by columns defined in the `columns` parameter.
- **except**: Group by all columns _except_ those in defined in the
`columns` parameter.
### tables
Input data. Default is piped-forward data (`<-`).
## Examples
- [Group by specific columns](#group-by-specific-columns)
- [Group by everything except time](#group-by-everything-except-time)
- [Ungroup data](#ungroup-data)
### Group by specific columns
```js
import "sampledata"
sampledata.int()
|> group(columns: ["_time", "tag"])
```
{{< expand-wrapper >}}
{{% expand "View example input and output" %}}
#### 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 |
| *_time | _value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:00Z | 19 | t2 |
| *_time | _value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:10Z | 10 | t1 |
| *_time | _value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:10Z | 4 | t2 |
| *_time | _value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:20Z | 7 | t1 |
| *_time | _value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:20Z | -3 | t2 |
| *_time | _value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:30Z | 17 | t1 |
| *_time | _value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:30Z | 19 | t2 |
| *_time | _value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:40Z | 15 | t1 |
| *_time | _value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:40Z | 13 | t2 |
| *_time | _value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:50Z | 4 | t1 |
| *_time | _value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:50Z | 1 | t2 |
{{% /expand %}}
{{< /expand-wrapper >}}
### Group by everything except time
```js
import "sampledata"
sampledata.int()
|> group(columns: ["_time"], mode: "except")
```
{{< expand-wrapper >}}
{{% expand "View example input and output" %}}
#### 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 |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:20Z | -3 | t2 |
| _time | *_value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:00Z | -2 | t1 |
| _time | *_value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:50Z | 1 | t2 |
| _time | *_value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:50Z | 4 | t1 |
| _time | *_value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:10Z | 4 | t2 |
| _time | *_value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:20Z | 7 | t1 |
| _time | *_value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:10Z | 10 | t1 |
| _time | *_value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:40Z | 13 | t2 |
| _time | *_value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:40Z | 15 | t1 |
| _time | *_value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:30Z | 17 | t1 |
| _time | *_value | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:00Z | 19 | t2 |
| 2021-01-01T00:00:30Z | 19 | t2 |
{{% /expand %}}
{{< /expand-wrapper >}}
### Ungroup data
```js
import "sampledata"
// Merge all tables into a single table
sampledata.int()
|> group()
```
{{< expand-wrapper >}}
{{% expand "View example input and output" %}}
#### 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 |
| 2021-01-01T00:00:10Z | 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 |
| 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 |
{{% /expand %}}
{{< /expand-wrapper >}}
Reference in New Issue View Git Blame Copy Permalink