drop() function

drop() 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 is removed from the key. If a specified column is not present in a table, the function returns an error.

Function type signature

(<-tables: stream[A], ?columns: [string], ?fn: (column: string) => bool) => stream[B] where A: Record, B: Record

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Parameters

columns

List of columns to remove 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

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

Drop a list of columns

import "sampledata"

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

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Input data

Output data

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Drop columns matching a predicate

import "sampledata"

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

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Input data

Output data

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