56 lines
1.6 KiB
Markdown
56 lines
1.6 KiB
Markdown
---
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title: findColumn() function
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description: >
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The `findColumn()` function returns an array of values in a specified column from the
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first table in a stream of tables where group key values match the specified predicate.
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aliases:
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- /influxdb/v2.0/reference/flux/stdlib/built-in/transformations/stream-table/findcolumn/
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- /influxdb/cloud/reference/flux/stdlib/built-in/transformations/stream-table/findcolumn/
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menu:
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flux_0_x_ref:
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name: findColumn
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parent: universe
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weight: 102
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flux/v0.x/tags: [dynamic queries]
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related:
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- /{{< latest "influxdb" >}}/query-data/flux/scalar-values/
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introduced: 0.68.0
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---
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The `findColumn()` function returns an array of values in a specified column from the
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first table in a stream of tables where the group key values match the specified predicate.
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The function returns an empty array if no table is found or if the column label
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is not present in the set of columns.
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```js
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findColumn(
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fn: (key) => key._field == "fieldName",
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column: "_value",
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)
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```
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## Parameters
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### fn {data-type="function"}
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A predicate function for matching keys in a table's group key.
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Expects a `key` argument that represents a group key in the input stream.
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### column {data-type="string"}
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Name of the column to extract.
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### tables {data-type="stream of tables"}
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Input data.
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Default is piped-forward data ([`<-`](/flux/v0.x/spec/expressions/#pipe-expressions)).
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## Example
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{{% flux/sample-example-intro %}}
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```js
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import "sampledata"
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sampledata.int()
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|> findColumn(fn: (key) => key.tag == "t1", column: "_value")
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// Returns [-2, 10, 7, 17, 15, 4]
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```
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