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

title	description	aliases	menu	weight	related	flux/v0.x/tags	introduced
drop() function	The `drop()` function removes specified columns from a table.	/influxdb/v2.0/reference/flux/functions/transformations/drop /influxdb/v2.0/reference/flux/functions/built-in/transformations/drop/ /influxdb/v2.0/reference/flux/stdlib/built-in/transformations/drop/ /influxdb/cloud/reference/flux/stdlib/built-in/transformations/drop/	flux_0_x_ref name parent drop universe	102	/flux/v0.x/stdlib/universe/keep/	transformations	0.7.0

The drop() function removes specified columns from a table. Columns are specified either through a list or a predicate function. When a dropped column is part of the group key, it will be removed from the key. If a specified column is not present in a table, it will return an error.

drop(columns: ["col1", "col2"])

// OR

drop(fn: (column) => column =~ /usage*/)

Parameters

{{% note %}} Make sure fn parameter names match each specified parameter. To learn why, see Match parameter names. {{% /note %}}

columns

Columns to removed from input tables. Mutually exclusive with fn.

fn

Predicate function with a column parameter that returns a boolean value indicating whether or not the column should be removed from input tables. Mutually exclusive with columns.

tables

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

Examples

{{% flux/sample-example-intro plural=true %}}

• Drop a list of columns
• Drop columns matching a predicate

Drop a list of columns

import "sampledata"

sampledata.int()
    |> drop(columns: ["_time", "tid"])

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

Input data

{{% flux/sample "int" %}}

{{% /flex-content %}} {{% flex-content %}}

Output data

_value
-2
10
7
17
15
4
19
4
-3
19
13
1

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

Drop columns matching a predicate

import "sampledata"

sampledata.int()
    |> drop(fn: (column) => column =~ /^t/)

{{% expand "View input and output" %}} {{< flex >}} {{% flex-content %}}

Input data

{{% flux/sample "int" %}}

{{% /flex-content %}} {{% flex-content %}}

Output data

_time	_value
2021-01-01T00:00:00Z	-2
2021-01-01T00:00:10Z	10
2021-01-01T00:00:20Z	7
2021-01-01T00:00:30Z	17
2021-01-01T00:00:40Z	15
2021-01-01T00:00:50Z	4
2021-01-01T00:00:00Z	19
2021-01-01T00:00:10Z	4
2021-01-01T00:00:20Z	-3
2021-01-01T00:00:30Z	19
2021-01-01T00:00:40Z	13
2021-01-01T00:00:50Z	1

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