docs-v2/content/flux/v0.x/stdlib/universe/findcolumn.md

1.6 KiB

title description aliases menu weight flux/v0.x/tags related introduced
findColumn() function The `findColumn()` function returns an array of values in a specified column from the first table in a stream of tables where group key values match the specified predicate.
/influxdb/v2.0/reference/flux/stdlib/built-in/transformations/stream-table/findcolumn/
/influxdb/cloud/reference/flux/stdlib/built-in/transformations/stream-table/findcolumn/
flux_0_x_ref
name parent
findColumn universe
102
dynamic queries
/{{< latest "influxdb" >}}/query-data/flux/scalar-values/
0.68.0

The findColumn() function returns an array of values in a specified column from the first table in a stream of tables where the group key values match the specified predicate. The function returns an empty array if no table is found or if the column label is not present in the set of columns.

findColumn(
    fn: (key) => key._field == "fieldName",
    column: "_value",
)

Parameters

fn

A predicate function for matching keys in a table's group key. Expects a key argument that represents a group key in the input stream.

column

Name of the column to extract.

tables

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

Example

{{% flux/sample-example-intro %}}

import "sampledata"

sampledata.int()
    |> findColumn(fn: (key) => key.tag == "t1", column: "_value")
    
// Returns [-2, 10, 7, 17, 15, 4]